CN116134058A - Acrylic rubber bag excellent in roll processability and banbury processability - Google Patents

Acrylic rubber bag excellent in roll processability and banbury processability Download PDF

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CN116134058A
CN116134058A CN202180056988.1A CN202180056988A CN116134058A CN 116134058 A CN116134058 A CN 116134058A CN 202180056988 A CN202180056988 A CN 202180056988A CN 116134058 A CN116134058 A CN 116134058A
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acrylic rubber
rubber bag
weight
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rubber
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增田浩文
川中孝文
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Zeon Corp
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    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/12—Esters of monohydric alcohols or phenols
    • C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
    • C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/12—Polymerisation in non-solvents
    • C08F2/16—Aqueous medium
    • C08F2/22—Emulsion polymerisation
    • C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/38—Polymerisation using regulators, e.g. chain terminating agents, e.g. telomerisation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F20/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
    • C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
    • C08F20/10—Esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/26—Esters containing oxygen in addition to the carboxy oxygen
    • C08F220/28—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety
    • C08F220/281—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety and containing only one oxygen, e.g. furfuryl (meth)acrylate or 2-methoxyethyl (meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F6/00—Post-polymerisation treatments
    • C08F6/14—Treatment of polymer emulsions
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F6/00—Post-polymerisation treatments
    • C08F6/14—Treatment of polymer emulsions
    • C08F6/22—Coagulation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
    • C08K3/013—Fillers, pigments or reinforcing additives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical

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Abstract

The invention provides an acrylic rubber bag with excellent roller processability and Banbury processability. The acrylic rubber bag of the present invention is composed of an acrylic rubber having a methyl ethyl ketone insoluble content of 50 wt% or less and an ash content of 0.4 wt% or less, and the acrylic rubber has at least one reactive group selected from a carboxyl group, an epoxy group and a chlorine atom, and has a ratio (Mw/Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) of 3.4 or more in an absolute molecular weight distribution measured by a GPC-MALS method using a dimethylformamide-based solvent as an eluting solvent.

Description

Acrylic rubber bag excellent in roll processability and banbury processability
Technical Field
The present invention relates to an acrylic rubber bag, a method for producing the same, a rubber composition, and a rubber crosslinked product, and more particularly, to an acrylic rubber bag excellent in roll processability and Banbury (Banbury) processability, and excellent in water resistance and compression set resistance of the crosslinked product, a method for producing the same, a rubber composition containing the same, and a rubber crosslinked product obtained by crosslinking the same.
Background
Acrylic rubber is a polymer containing an acrylic ester as a main component, and is generally known as a rubber excellent in heat resistance, oil resistance and ozone resistance, and is widely used in fields related to automobiles, and the like.
For example, patent document 1 (pamphlet of international publication No. 2019/188709) discloses the following method: adding monomer components composed of ethyl acrylate, butyl acrylate, methoxyethyl acrylate and monobutyl fumarate, water and sodium lauryl sulfate, repeatedly degassing under reduced pressure and replacing nitrogen, adding sodium aldehyde sulfoxylate and cumene hydroperoxide as an organic radical generator, initiating emulsion polymerization at normal pressure and normal temperature, performing emulsion polymerization until the polymerization conversion reaches 95 weight percent, solidifying with calcium chloride aqueous solution, filtering with a metal mesh, and dehydrating and drying with an extrusion dryer with a screw to prepare the acrylic rubber. However, the acrylic rubber obtained by this method has problems of extremely poor roll processability and banbury processability, and also poor storage stability and water resistance.
Patent document 2 (japanese patent application laid-open No. 2019-119772) discloses the following method: after a monomer emulsion was prepared from a monomer component comprising ethyl acrylate, butyl acrylate, methoxyethyl acrylate and monobutyl maleate using pure water and sodium lauryl sulfate and polyoxyethylene lauryl ether as emulsifiers, a part of the monomer emulsion was put into a polymerization tank, cooled to 12℃under a nitrogen stream, then the remaining part of the monomer emulsion, ferrous sulfate, sodium ascorbate and an aqueous potassium persulfate solution as an inorganic radical generator were continuously added dropwise over 3 hours, and then the emulsion polymerization was continued at 23℃for 1 hour until the polymerization conversion reached 97% by weight, and then heated to 85℃and then sodium sulfate was continuously added, whereby aqueous pellets were coagulated and filtered, and after 4 times of washing with water, 1 time of washing with acid and 1 time of washing with pure water, acrylic rubber was continuously produced into a sheet form by an extruder dryer having a screw, and crosslinked with an aliphatic polyamine compound such as hexamethylenediamine carbamate. However, the sheet-like acrylic rubber obtained by this method has problems of poor roll processability and poor water resistance of the crosslinked product. In addition, patent document 2 does not describe the encapsulation of the sheet-like acrylic rubber obtained.
Patent document 3 (japanese patent application laid-open No. 1-135811) discloses the following method: a monomer composition comprising ethyl acrylate, caprolactone-added acrylate, cyanoethyl acrylate and vinyl chloride is prepared, 1/4 of the monomer mixture comprising the above monomer composition and n-dodecyl mercaptan as a chain transfer agent is emulsified with sodium lauryl sulfate, polyethylene glycol nonylphenyl ether and distilled water, sodium sulfite and ammonium persulfate as an inorganic radical generator are added to initiate polymerization, the polymerization is initiated by dropwise adding the remaining part of the monomer mixture and a 2% aqueous solution of ammonium persulfate while maintaining the temperature at 60℃for 2 hours, the polymerization is continued for 2 hours after the dropwise addition, and latex having a polymerization conversion of 96 to 99% is put into a 80℃aqueous solution of sodium chloride to be coagulated, and then dried after sufficient water washing, whereby an acrylic rubber is produced and crosslinked with sulfur. However, the acrylic rubber obtained by this method has problems of poor roll processability and storage stability, and poor strength characteristics and water resistance of the crosslinked product.
Patent document 4 (japanese patent application laid-open No. 2018-168343) discloses the following method: preparing monomer components composed of ethyl acrylate, butyl acrylate and monobutyl fumarate, preparing monomer emulsion composed of the monomer components, pure water, sodium lauryl sulfate, polyethylene glycol monostearate and n-dodecyl mercaptan serving as a chain transfer agent, then charging a part of the monomer emulsion and pure water into a polymerization reaction tank, cooling to 12 ℃, continuously dropwise adding the rest of the monomer emulsion, ferrous sulfate, sodium ascorbate and potassium persulfate serving as an inorganic free radical generator for 2.5 hours, keeping the temperature at 23 ℃ for 1 hour, continuously adding sodium sulfate at 85 ℃ after industrial water is heated to 85 ℃, solidifying to obtain water granules, washing with pure water for 3 times, drying with a hot air dryer, and crosslinking with 2, 2-bis [4- (4-aminophenoxy) phenyl ] propane. However, the acrylic rubber obtained by this method is excellent in stress relaxation property and extrusion processability, but has problems of insufficient roll processability and storage stability, and poor strength characteristics and water resistance of a crosslinked product.
Patent document 5 (japanese patent application laid-open No. 9-143229) discloses the following method: a monomer mixture composed of ethyl acrylate, a special acrylic ester and vinyl monochloroacetate, sodium lauryl sulfate as an emulsifier, n-octanethiol as a chain transfer agent and water are added into a reaction vessel, nitrogen substitution is carried out, then ammonium bisulfide and sodium persulfate as an inorganic free radical generator are added to initiate polymerization reaction, copolymerization is carried out for 3 hours at 55 ℃ with a reaction conversion rate of 93-96%, and acrylic rubber is produced, and crosslinking is carried out by sulfur. However, the acrylic rubber obtained by the method has problems of poor storage stability and poor strength characteristics and water resistance of the crosslinked product.
Patent document 6 (Japanese patent application laid-open No. 62-64809) discloses an acrylic rubber which is excellent in processability, compression set and tensile strength and can be vulcanized with sulfur, characterized in that it is a copolymer composed of 50 to 99.9% by weight of at least one compound selected from alkyl acrylate and alkoxyalkyl acrylate, 0.1 to 20% by weight of a dicyclopentadienyl group-containing ester of unsaturated carboxylic acid having a radical-reactive group, 0 to 20% by weight of other monomer composed of at least one of monovinyl, mono1, 1-vinylidene and mono1, 2-vinylidene unsaturated compound, and has a number average molecular weight in terms of polystyrene in which tetrahydrofuran is used as an eluting solvent The (Mn) is 20 to 120 tens of thousands, and the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 10 or less. It is also described that the number average molecular weight (Mn) is 20 to 100 ten thousand, preferably 20 to 100 ten thousand, and if Mn is less than 20 ten thousand, the physical properties and processability of the sulfide are poor, if it is more than 120 ten thousand, and the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is not preferable, and if it is more than 10, compression set becomes large. As specific examples thereof, the following manufacturing methods are disclosed: the addition amount of the acrylic rubber is changed, and the acrylic rubber is polymerized to obtain an acrylic rubber having a number average molecular weight (Mn) of 53 to 115 ten thousand, a weight average molecular weight (Mw) of 354 to 626 ten thousand and a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 4.7 to 8, after solidification in a calcium chloride aqueous solution, the acrylic rubber is sufficiently washed with water and directly dried. Further, it is shown in examples and comparative examples that when the amount of the chain transfer agent is small, the number average molecular weight (Mn) of the obtained acrylic rubber is as high as 500 ten thousand, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) becomes narrow as 1.4, and when the amount of the chain transfer agent is large, the number average molecular weight (Mn) is as small as 20 ten thousand, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) becomes extremely wide as 17. However, the acrylic rubber obtained by the present method has poor compression set resistance and storage stability, and therefore has a problem that the roll processability and banbury processability are insufficient because the acrylic rubber has a large and excessively complex molecular weight (Mw, mn) even if an appropriate molecular weight distribution (Mw/Mn) is obtained in a polymerization reaction using a radical generator. In addition, the acrylic rubber obtained by the present method was kneaded with a roll by adding sulfur as a crosslinking agent and a vulcanization accelerator in a crosslinking reaction, and then subjected to 100kg/cm at 170℃for 15 minutes 2 The vulcanization press of (a) and crosslinking at 175℃for 4 hours with a Gill oven (binder over) have a problem that long-time crosslinking is required, and the resulting crosslinked product has compression set resistance, water resistance and strength characteristicsAnd also poor in physical properties after thermal degradation.
On the other hand, as a method for producing a rubber-coated acrylic rubber, for example, patent document 7 (japanese unexamined patent publication No. 2006-328239) discloses a method for producing a rubber polymer comprising the steps of: a step of contacting a polymer latex with a coagulating liquid to obtain a pellet slurry containing a pellet-like rubber polymer; using stirring power of 1kW/m 3 The above-mentioned stirrer having a stirring/pulverizing function pulverizes the crumb rubber polymer contained in the crumb slurry; a dehydration step of removing water from the crumb slurry in which the crumb rubber polymer is crushed to obtain a crumb rubber polymer; a step of heating and drying the water-removed crumb rubber polymer; it is also described that the dried pellets are introduced into a baler in the form of tablets (flaps) for encapsulation by compression. The rubber polymer used herein specifically shows an unsaturated nitrile-conjugated diene copolymer latex obtained by emulsion polymerization, and also shows a copolymer composed only of an acrylic ester such as an ethyl acrylate/n-butyl acrylate copolymer, an ethyl acrylate/n-butyl acrylate/2-methoxyethyl acrylate copolymer, and the like. However, an acrylic rubber composed only of an acrylic ester has a problem of poor properties of crosslinked rubber such as heat resistance and compression set resistance.
As an acrylic rubber having an ion-reactive group and being encapsulated, which is excellent in heat resistance and compression set resistance, for example, patent document 8 (pamphlet of international publication No. 2018/116828) discloses the following method: the monomer components consisting of ethyl acrylate, n-butyl acrylate and mono-n-butyl fumarate were emulsified with sodium lauryl sulfate, polyethylene glycol monostearate and water as emulsifiers, cumene hydroperoxide as an organic radical generator was added to the emulsion polymerization until the polymerization conversion reached 95%, the resulting acrylic rubber latex was added to an aqueous solution of magnesium sulfate and dimethylamine-ammonia-epichlorohydrin polycondensate as a polymeric flocculant, followed by stirring at 85℃to give a pellet slurry, and the pellet slurry was washed with water 1 time, and the whole was passed through a 100-mesh metal mesh to collect only solid components, thereby recovering the acrylic rubber in pellet form. According to this method, it is described that the pellets in the water-containing state obtained are dehydrated by centrifugal separation or the like, dried at 50 to 120 ℃ by a belt dryer or the like, and introduced into a baler to be compressed and baled. However, in this method, there is: in the coagulation reaction, a large amount of water-containing aggregates in a semi-coagulated state are generated, and a large amount of water-containing aggregates adhere to the coagulation tank, and therefore, the problem of sufficiently removing the coagulant and the emulsifier by washing is not solved, and the problem of poor roll processability, banbury processability, and water resistance of the acrylic rubber itself, insufficient removal of air even when producing a rubber bag, and poor storage stability is also solved.
Prior art literature
Patent literature
Patent document 1: international publication No. 2019/188709;
patent document 2: japanese patent application laid-open No. 2019-119772;
patent document 3: japanese patent laid-open No. 1-135811;
patent document 4: japanese patent application laid-open No. 2018-168343;
patent document 5: japanese patent laid-open No. 9-143229;
patent document 6: japanese patent laid-open No. 62-64809;
patent document 7: japanese patent laid-open No. 2006-328239;
patent document 8: international publication No. 2018/116828 pamphlet.
Disclosure of Invention
Problems to be solved by the invention
The present invention has been made in view of the above-described circumstances of the prior art, and an object of the present invention is to provide an acrylic rubber bag having excellent roll processability and banbury processability and a crosslinked product having a high balance between water resistance and compression set resistance, a method for producing the same, a rubber composition comprising the acrylic rubber bag, and a crosslinked rubber product obtained by crosslinking the same.
Solution for solving the problem
The present inventors have made intensive studies in view of the above problems, and as a result, have found that an acrylic rubber bag made of an acrylic rubber having a specific reactive group and having an absolute molecular weight distribution in terms of weight average molecular weight (Mw) and number average molecular weight (Mn) ratio (Mw/Mn) in a specific range, having an insoluble component amount of a specific solvent and an ash amount in a specific range is excellent in roll processability and banbury processability, and that a crosslinked product is highly balanced and excellent in water resistance and compression set resistance.
The present inventors have found that an acrylic rubber bag made of an acrylic rubber having a reactive group capable of reacting with a crosslinking agent such as a carboxyl group, an epoxy group, a chlorine atom, etc., is excellent in short-time crosslinkability, strength characteristics, and compression set resistance.
The present inventors have also found that, in GPC measurement of an acrylic rubber having such a reactive group, the above-mentioned conventional radical-reactive acrylic rubber obtained by copolymerizing ethyl acrylate, dicyclopentenyl acrylate, or the like is not sufficiently dissolved in tetrahydrofuran used for GPC measurement, and each molecular weight and molecular weight distribution cannot be measured perfectly and reproducibly well, but by using a specific solvent having an SP value higher than that of tetrahydrofuran as an eluting solvent, it is possible to measure perfectly and reproducibly well, and by specifying each characteristic value, the roll processability and banbury processability of an acrylic rubber bag are excellent, and the water resistance and compression set resistance properties of a crosslinked product can be highly balanced.
The present inventors have found that the roll processability of an acrylic rubber bag is greatly related to the number average molecular weight (Mn), the weight average molecular weight (Mw) and the ratio of the number average molecular weight (Mn) (Mw/Mn) of the acrylic rubber constituting the acrylic rubber bag as measured by the GPC-MALS method, and that when the respective ratios are within specific ranges, the roll processability can be remarkably improved without impairing the strength characteristics. In particular, the larger the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), the more improved the roll processability, and although it is difficult to produce an acrylic rubber having a specific number average molecular weight (Mn) and a wide ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), the present inventors have found that it can be achieved by adding it in portions during polymerization without adding a chain transfer agent in the beginning. Further, the present inventors have found that by drying the aqueous pellets produced in the coagulation reaction with high shear using a screw type biaxial extrusion dryer, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is greatly widened, and the roll processability is further improved without impairing the number average molecular weight (Mn).
The present inventors found that, regarding the banbury workability, the smaller the amount of methyl ethyl ketone insoluble component of the acrylic rubber bag, the more excellent. It was found that the amount of the methyl ethyl ketone insoluble component of the acrylic rubber bag was generated during the polymerization reaction, and particularly, it was drastically increased and difficult to control when the polymerization conversion rate was increased in order to improve the strength characteristics, but emulsion polymerization was performed in the presence of a chain transfer agent in the latter half of the polymerization reaction, and it was possible to suppress to some extent, and regarding the drastically increased methyl ethyl ketone insoluble component, the acrylic rubber was melt kneaded and extrusion-dried in a substantially moisture-free state (moisture content less than 1% by weight) in a screw type biaxial extrusion dryer, and the drastically increased methyl ethyl ketone insoluble component was disappeared without deviation, and the banbury processability was remarkably improved without impairing the roll processability of the acrylic rubber bag. The present inventors have also found that the banbury processability and the strength characteristics of an acrylic rubber bag produced by melt extrusion in a state in which water is almost removed by a screw type biaxial extrusion dryer are highly balanced.
The present inventors have also found that the ash content and ash content in the acrylic rubber bag have a great influence on the water resistance of the acrylic rubber bag. It was found that the ash amount of the acrylic rubber using a large amount of an emulsifier and a coagulant in emulsion polymerization is hardly reduced, but the washing efficiency in hot water and the ash removal efficiency in dehydration of the aqueous pellets produced by coagulation by a specific method are remarkably improved, and as a result, the water resistance of the acrylic rubber bag can be remarkably improved. The present inventors have found that, in particular, by increasing the ratio of the specific particle size of the aqueous aggregates formed in the coagulation step and performing washing/dewatering/drying, the water resistance can be significantly improved without impairing the properties such as the roll processability, the banbury processability, the strength properties and the compression set resistance of the obtained acrylic rubber bag. Further, the present inventors have found that when a specific emulsifier is used in emulsion polymerization of acrylic rubber or a specific coagulant is used in the case of coagulating an emulsion polymerization liquid, the acrylic rubber bag is excellent in water resistance and is remarkably improved in releasability from a metal mold or the like.
The present inventors have also found that when the acrylic rubber constituting the acrylic rubber bag has a specific reactive group and the weight average molecular weight (Mw), the ratio of the z-average molecular weight (Mz) to the weight average molecular weight (Mw) (Mz/Mw) is specified, the crosslinkability of the crosslinked product of the acrylic rubber bag, the normal physical properties including compression set resistance and strength properties are highly balanced.
Further, the present inventors have found that by increasing the specific gravity of the acrylic rubber bag, the roll processability, the banbury processability, the water resistance, the strength characteristics and the compression set characteristics are excellent, and the storage stability is also greatly improved. It was found that an acrylic rubber having a specific reactive group has tackiness and is not easily removed by air, and a large amount of air is involved in a pellet-like acrylic rubber obtained by directly drying an aqueous pellet (specific gravity becomes small), and storage stability becomes poor, but by rubber-packing the pellet-like acrylic rubber with a packer or the like, a small amount of air can be removed and storage stability can be improved, and by extrusion-drying an aqueous pellet under reduced pressure by a screw type biaxial extrusion dryer and extruding and laminating in an air-free sheet, a rubber-packed acrylic rubber containing little air and having a high specific gravity and significantly improved storage stability can be produced. Furthermore, the present inventors have found that the specific gravity considering the air content can be measured according to the a method of cross-linked rubber-density measurement using JIS K6268 which is a buoyancy difference. It was also found that the storage stability of the acrylic rubber bag can be further improved by a specific pH.
The present inventors have also found that by increasing the cooling rate after drying, the mooney scorch stability can be significantly improved without impairing the properties such as roll processability, banbury processability, water resistance, strength properties, compression set resistance and the like of the acrylic rubber bag.
The present inventors have also found that emulsion polymerization is initiated by emulsifying a specific monomer component with water and an emulsifier, and then in the presence of a redox catalyst composed of an inorganic radical generator such as potassium persulfate and a reducing agent, and that the emulsion polymerization is carried out in batch during the polymerization without adding a chain transfer agent at the beginning; solidifying the emulsion polymerization liquid under specific conditions; washing the aqueous granules produced in the coagulation reaction with hot water; and dehydrating the cleaned water-containing granules, drying, and carrying out gel coating; the acrylic rubber obtained by this method has a high molecular weight component and a low molecular weight component which coexist to form a broad molecular weight distribution, and a specific ash content of a specific component and an insoluble component content of a specific solvent are specified, whereby the roll processability, banbury processability, strength characteristics, compression set resistance and water resistance of the obtained acrylic rubber bag are highly balanced.
The present inventors have also found that an acrylic rubber bag having further improved roll processability, strength characteristics and water resistance can be produced by melt-kneading and drying an acrylic rubber under high shear conditions using a specific extrusion dryer. Further, it has been found that by specifying the post-addition of a reducing agent and the polymerization temperature, an acrylic rubber bag having a further balance among roll processability, strength characteristics and water resistance can be produced.
The present inventors have further found that by blending carbon black and silica as fillers in the rubber composition comprising the acrylic rubber bag, filler and crosslinking agent of the present invention, the roll processability, banbury processability and short-time crosslinkability are excellent, and the water resistance, strength characteristics and compression set resistance of the crosslinked product are highly excellent. The present inventors have also found that, as the crosslinking agent, an organic compound, a polyvalent compound or an ionic crosslinking compound, for example, a polyvalent ionic organic compound having a plurality of ion-reactive groups capable of reacting with the ion-reactive groups of the acrylic rubber bag, such as an amine group, an epoxy group, a carboxyl group or a thiol group, is preferable, whereby the roll processability, the banbury processability and the crosslinking property in a short period of time are excellent, and the water resistance, the strength property and the compression set resistance of the crosslinked product are highly excellent.
The present inventors have completed the present invention based on these findings.
Thus, according to the present invention, there can be provided an acrylic rubber bag comprising an acrylic rubber having an insoluble methyl ethyl ketone content of 50 wt% or less and an ash content of 0.4 wt% or less, wherein the acrylic rubber has a reactive group selected from at least one of a carboxyl group, an epoxy group and a chlorine atom, and wherein the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the absolute molecular weight distribution measured by GPC-MALS method using a dimethylformamide-based solvent as an eluting solvent is 3.4 or more.
In the acrylic rubber bag of the present invention, the amount of methyl ethyl ketone insoluble component is preferably 10% by weight or less.
In the acrylic rubber bag of the present invention, the values when the amount of methyl ethyl ketone insoluble component at 20 points is measured are preferably all within the range of (average ± 5% by weight).
In the acrylic rubber bag of the present invention, the specific gravity is preferably 0.8 or more.
In the acrylic rubber bag of the present invention, the ash content is preferably in the range of 0.001 to 0.2% by weight.
In the acrylic rubber bag of the present invention, the total amount of sodium, magnesium, calcium, phosphorus and sulfur in ash is preferably 50% by weight or more.
In the acrylic rubber bag of the present invention, the total amount of magnesium and phosphorus in ash is preferably 50% by weight or more.
In the acrylic rubber bag of the present invention, the weight average molecular weight (Mw) of the absolute molecular weight measured by GPC-MALS method is preferably 100 ten thousand or more.
In the acrylic rubber bag of the present invention, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the absolute molecular weight distribution measured by GPC-MALS method is preferably 3.5 or more.
In the acrylic rubber bag of the present invention, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the absolute molecular weight distribution measured by GPC-MALS method is preferably 3.8 or more.
In the acrylic rubber bag of the present invention, the ratio (Mz/Mw) of the z-average molecular weight (Mz) to the weight-average molecular weight (Mw) of the absolute molecular weight distribution measured by GPC-MALS method is preferably 1.3 or more.
In the acrylic rubber bag of the present invention, the acrylic rubber is preferably emulsion-polymerized using a phosphate salt or a sulfate salt as an emulsifier, and the acrylic rubber is preferably coagulated and dried by using an alkali metal salt or a group 2 metal salt of the periodic table as a coagulant. In the acrylic rubber bag of the present invention, the acrylic rubber is preferably melt-kneaded and dried after solidification, and the melt-kneaded and dried are preferably carried out in a state substantially free of moisture, and the melt-kneaded and dried are preferably carried out under reduced pressure. In the acrylic rubber bag of the present invention, the acrylic rubber is preferably cooled at a cooling rate of 40℃per hour or more after the melt-kneading and drying.
In the acrylic rubber bag of the present invention, it is preferable to wash, dehydrate and dry the aqueous pellet having a particle diameter in the range of 710 μm to 6.7mm in a proportion of 50 wt% or more.
Further, according to the present invention, there is provided a method for producing an acrylic rubber bag, comprising the steps of:
an emulsifying step of emulsifying an acrylic rubber monomer component containing a monomer having a reactive group selected from at least one of a carboxyl group, an epoxy group, and a chlorine atom with water and an emulsifier;
an emulsion polymerization step of initiating polymerization in the presence of a redox catalyst containing an inorganic radical generator and a reducing agent, and adding a chain transfer agent in a batch after the polymerization step to continue the polymerization, thereby obtaining an emulsion polymerization solution;
a coagulation step of adding the emulsion polymerization liquid obtained to the stirred coagulation liquid to coagulate the emulsion polymerization liquid, thereby producing an aqueous pellet;
a washing step of washing the produced hydrous pellets with hot water;
a dehydration step of dehydrating the washed aqueous pellets;
a drying step of drying the dehydrated aqueous pellets to less than 1 wt%;
and a rubber coating step of coating the dried rubber with rubber.
The method for producing the acrylic rubber bag of the present invention is preferably to produce the acrylic rubber bag.
In the method for producing an acrylic rubber bag of the present invention, in the emulsion polymerization step, emulsion polymerization is preferably performed using a phosphate salt or a sulfate salt as an emulsifier.
In the method for producing an acrylic rubber bag of the present invention, it is preferable to coagulate the polymerization liquid produced in the emulsion polymerization step by using an alkali metal salt or a group 2 metal salt of the periodic table as a coagulant, and then dry the coagulated polymerization liquid.
In the method for producing an acrylic rubber bag of the present invention, it is preferable that the polymerization liquid produced in the emulsion polymerization step is added to an aqueous solution containing a coagulant containing an alkali metal salt or a group 2 metal salt of the periodic table and stirred to be coagulated.
In the method for producing an acrylic rubber bag of the present invention, it is preferable that the polymerization liquid produced in the emulsion polymerization step is brought into contact with a coagulant, and is solidified, and then melt kneaded and dried.
In the method for producing an acrylic rubber bag of the present invention, it is preferable that the melt kneading and drying are carried out in a state substantially free from moisture.
In the method for producing an acrylic rubber bag of the present invention, the above-mentioned melt kneading and drying are preferably carried out under reduced pressure.
In the method for producing an acrylic rubber bag of the present invention, the acrylic rubber after melt-kneading and drying is preferably cooled at a cooling rate of 40℃per hour or more.
In the method for producing an acrylic rubber bag of the present invention, it is preferable to wash, dehydrate and dry the aqueous pellet having a particle diameter in the range of 710 μm to 6.7mm in a proportion of 50% by weight or more.
Further, according to the present invention, there can be provided a rubber composition comprising a rubber component containing the above-mentioned acrylic rubber bag, a filler and a crosslinking agent.
In the rubber composition of the present invention, the filler is preferably a reinforcing filler. In the rubber composition of the present invention, the filler is preferably carbon black. In the rubber composition of the present invention, the filler is preferably silica.
In the rubber composition of the present invention, the crosslinking agent is preferably an organic crosslinking agent. In the rubber composition of the present invention, the crosslinking agent is preferably a polyvalent compound. In the rubber composition of the present invention, it is preferable that the crosslinking agent is an ion-crosslinkable compound. In the rubber composition of the present invention, the crosslinking agent is preferably an ion-crosslinkable organic compound. In the rubber composition of the present invention, the crosslinking agent is preferably a polyionic organic compound.
In the rubber composition of the present invention, the ion of the ion-crosslinkable compound, ion-crosslinkable organic compound or polyion-crosslinkable organic compound as the crosslinking agent is preferably an ion-reactive group selected from at least one of amino group, epoxy group, carboxyl group and thiol group.
In the rubber composition of the present invention, the crosslinking agent is preferably a polyion compound selected from at least one of a polyamine compound, a polyepoxide compound, a polycarboxylic acid compound and a polythiol compound.
In the rubber composition of the present invention, the content of the crosslinking agent is preferably in the range of 0.001 to 20 parts by weight relative to 100 parts by weight of the rubber component.
The rubber composition of the present invention preferably further comprises an anti-aging agent. In the rubber composition of the present invention, the antioxidant is preferably an amine-based antioxidant.
Further, according to the present invention, there is provided a method for producing a rubber composition, comprising mixing a rubber component comprising the above-mentioned acrylic rubber bag, a filler, and an antioxidant, if necessary, and then mixing a crosslinking agent.
Further, according to the present invention, there can be provided a crosslinked rubber product obtained by crosslinking the above-mentioned rubber composition. In the rubber crosslinked product of the present invention, the crosslinking of the rubber composition is preferably performed after molding. In the rubber crosslinked product of the present invention, it is preferable that the crosslinking of the rubber composition is a crosslinking in which primary crosslinking and secondary crosslinking are performed.
Effects of the invention
According to the present invention, there can be provided an acrylic rubber bag excellent in roll processability and banbury processability and having a high balance of water resistance and compression set resistance of a crosslinked product, an efficient production method thereof, a high-quality rubber composition comprising the acrylic rubber bag, and a crosslinked rubber product obtained by crosslinking the composition.
Drawings
Fig. 1 is a diagram schematically showing an example of an acrylic rubber manufacturing system for manufacturing an acrylic rubber bag according to an embodiment of the present invention.
Fig. 2 is a view showing the structure of the screw extruder of fig. 1.
Fig. 3 is a diagram showing a structure of a conveying type cooling device serving as the cooling device of fig. 1.
Detailed Description
The acrylic rubber bag of the present invention is characterized in that it comprises an acrylic rubber having a methyl ethyl ketone insoluble content of 50 wt.% or less and an ash content of 0.4 wt.% or less, the acrylic rubber having a reactive group selected from at least one of a carboxyl group, an epoxy group and a chlorine atom, and a ratio (Mw/Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) of an absolute molecular weight distribution measured by GPC-MALS method using a dimethylformamide-based solvent as an eluting solvent being 3.4 or more. The term "GPC-MALS method" as used herein refers to the following. GPC (gel permeation chromatography ) is a liquid chromatography method for separation based on differences in molecular size. A multi-angle laser light scattering detector (MALS) and a differential refractive index detector (RI) are assembled in the device, and the GPC device is used for measuring the light scattering intensity and refractive index difference of a molecular chain solution classified according to the size according to the dissolution time, thereby sequentially calculating the molecular weight of solute and the content thereof, and finally obtaining the absolute molecular weight distribution and absolute average molecular weight value of the polymer substance.
< reactive group >
The acrylic rubber bag of the present invention has at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom.
The reactive group selected from at least one of a carboxyl group, an epoxy group and a chlorine atom is not particularly limited, but is preferably an ion-reactive group that performs an ion reaction, more preferably an epoxy group and a carboxyl group, particularly preferably a carboxyl group, and in this case, the crosslinkability in a short period of time and the compression set resistance and water resistance of the crosslinked product can be improved to a high degree.
The content of the reactive group selected from at least one of a carboxyl group, an epoxy group and a chlorine atom in the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and the weight ratio of the reactive group itself is usually in the range of 0.001 to 5% by weight, preferably in the range of 0.01 to 3% by weight, more preferably in the range of 0.05 to 1% by weight, and particularly preferably in the range of 0.1 to 0.5% by weight, and in this case, the processability, crosslinkability, and strength characteristics, compression set resistance, oil resistance, cold resistance, water resistance and the like of the acrylic rubber bag are highly balanced, and therefore, the acrylic rubber bag is preferable.
The acrylic rubber bag having at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom of the present invention may be an acrylic rubber bag in which at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom is introduced into an acrylic rubber by post-reaction, but is preferably an acrylic rubber in which the reactive group-containing monomer is copolymerized.
< monomer component >
The monomer component of the acrylic rubber constituting the acrylic rubber bag of the present invention is not particularly limited as long as it is a monomer that constitutes an acrylic rubber in general, but is preferably an acrylic rubber monomer component containing a monomer containing at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom, more preferably a monomer component composed of at least one (meth) acrylate selected from the group consisting of an alkyl (meth) acrylate and an alkoxyalkyl (meth) acrylate, a monomer containing at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom, and other monomer copolymerizable as necessary. In the present invention, "(meth) acrylate" is used as a term for esters of acrylic acid and/or methacrylic acid.
The preferable monomer component of the acrylic rubber of the present invention is a monomer component composed of at least one (meth) acrylic acid ester selected from the group consisting of alkyl (meth) acrylates and alkoxyalkyl (meth) acrylates, a monomer containing at least one reactive group selected from the group consisting of carboxyl groups, epoxy groups, and chlorine atoms, and other monomers copolymerizable as needed.
The alkyl (meth) acrylate is not particularly limited, and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms is generally used, and an alkyl (meth) acrylate having an alkyl group having 1 to 8 carbon atoms is preferable, and an alkyl (meth) acrylate having an alkyl group having 2 to 6 carbon atoms is more preferable.
Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like, and among these, ethyl (meth) acrylate, n-butyl (meth) acrylate, and more preferably ethyl acrylate and n-butyl acrylate.
The alkoxyalkyl (meth) acrylate is not particularly limited, and an alkoxyalkyl (meth) acrylate having an alkoxyalkyl group having 2 to 12 carbon atoms is generally used, and an alkoxyalkyl (meth) acrylate having an alkoxyalkyl group having 2 to 8 carbon atoms is preferable, and an alkoxyalkyl (meth) acrylate having an alkoxyalkyl group having 2 to 6 carbon atoms is more preferable.
Specific examples of the alkoxyalkyl (meth) acrylate include methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, methoxybutyl (meth) acrylate, ethoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, and the like. Among these, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, and the like are preferable, and methoxyethyl acrylate and ethoxyethyl acrylate are more preferable.
These (meth) acrylic esters selected from at least one of alkyl (meth) acrylate and alkoxyalkyl (meth) acrylate may be used alone or in combination of two or more, and the proportion of these in the whole monomer components is usually in the range of 50 to 99.99% by weight, preferably in the range of 62 to 99.95% by weight, more preferably in the range of 74 to 99.9% by weight, particularly preferably in the range of 80 to 99.5% by weight, most preferably in the range of 87 to 99% by weight, and at this time, the weather resistance, heat resistance and oil resistance of the acrylic rubber are highly excellent and therefore preferable.
The monomer containing at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom is suitably selected according to the purpose of use, and is preferably a monomer having a carboxyl group and an epoxy group, more preferably a monomer having a carboxyl group, and in this case, the crosslinkability in a short period of time and the compression set resistance and water resistance of the crosslinked product can be highly improved, and therefore, it is preferable.
The monomer having a carboxyl group is not particularly limited, and an ethylenically unsaturated carboxylic acid can be preferably used. Examples of the ethylenically unsaturated carboxylic acid include ethylenically unsaturated monocarboxylic acid, ethylenically unsaturated dicarboxylic acid, and ethylenically unsaturated dicarboxylic acid monoester, and among these, particularly, ethylenically unsaturated dicarboxylic acid monoester is preferable because it can further improve compression set resistance when the acrylic rubber is made into a rubber crosslinked product.
The ethylenically unsaturated monocarboxylic acid is not particularly limited, but preferably has 3 to 12 carbon atoms, and examples thereof include acrylic acid, methacrylic acid, α -ethacrylic acid, crotonic acid, cinnamic acid, and the like.
The ethylenically unsaturated dicarboxylic acid is not particularly limited, but preferably an ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms, and examples thereof include: butenedioic acids such as fumaric acid and maleic acid; itaconic acid; citraconic acid, and the like. In addition, the ethylenically unsaturated dicarboxylic acid also includes ethylenically unsaturated dicarboxylic acids present as anhydrides.
The ethylenically unsaturated dicarboxylic acid monoester is not particularly limited, but is usually an alkyl monoester having 1 to 12 carbon atoms of an ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms, preferably an alkyl monoester having 2 to 8 carbon atoms of an ethylenically unsaturated dicarboxylic acid having 4 to 6 carbon atoms, and more preferably an alkyl monoester having 2 to 6 carbon atoms of a butenedioic acid having 4 carbon atoms.
Specific examples of the ethylenically unsaturated dicarboxylic acid monoester include: mono-alkyl butenedioates such as monomethyl fumarate, monoethyl fumarate, mono-n-butyl fumarate, monomethyl maleate, monoethyl maleate, mono-n-butyl maleate, monocyclopentyl fumarate, monocyclohexyl fumarate, monocyclohexenyl fumarate, monocyclopentyl maleate, monocyclohexyl maleate, and the like; mono-alkyl itaconates such as monomethyl itaconate, monoethyl itaconate, mono-n-butyl itaconate and monocyclohexyl itaconate, and among these, mono-n-butyl fumarate and mono-n-butyl maleate are preferable, and mono-n-butyl fumarate is particularly preferable.
Examples of the monomer having an epoxy group include: epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate; vinyl ethers containing an epoxy group such as allyl glycidyl ether and vinyl glycidyl ether.
Examples of the monomer having a chlorine atom include, but are not particularly limited to, unsaturated alcohol esters of saturated carboxylic acids having a chlorine atom, chloroalkyl (meth) acrylates, chloroacyloxyalkyl (meth) acrylates, (chloroacetylcarbamoyloxy) alkyl (meth) acrylates, unsaturated ethers having a chlorine atom, unsaturated ketones having a chlorine atom, aromatic vinyl compounds having a chloromethyl group, unsaturated amides having a chlorine atom, and chloroacetyl unsaturated monomers.
Specific examples of the unsaturated alcohol ester of a saturated carboxylic acid containing a chlorine atom include vinyl chloroacetate, vinyl 2-chloropropionate, allyl chloroacetate, and the like. Specific examples of the chloroalkyl (meth) acrylate include chloromethyl (meth) acrylate, 1-chloroethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 1, 2-dichloroethyl (meth) acrylate, 2-chloropropyl (meth) acrylate, 3-chloropropyl (meth) acrylate, and 2, 3-dichloropropyl (meth) acrylate. Specific examples of the chloroacetoxy alkyl (meth) acrylate include 2- (chloroacetoxy) ethyl (meth) acrylate, 2- (chloroacetoxy) propyl (meth) acrylate, 3- (chloroacetoxy) propyl (meth) acrylate, and 3- (hydroxychloroacetoxy) propyl (meth) acrylate. Examples of the (chloroacetylcarbamoyloxy) alkyl (meth) acrylate include 2- (chloroacetylcarbamoyloxy) ethyl (meth) acrylate and 3- (chloroacetylcarbamoyloxy) propyl (meth) acrylate. Specific examples of the unsaturated ether containing chlorine atoms include chloromethyl vinyl ether, 2-chloroethyl vinyl ether, 3-chloropropyl vinyl ether, 2-chloroethyl allyl ether, and 3-chloropropyl allyl ether. Specific examples of the unsaturated ketone containing chlorine atom include 2-chloroethyl vinyl ketone, 3-chloropropyl vinyl ketone, and 2-chloroethyl allyl ketone. Specific examples of the chloromethyl-containing aromatic vinyl compound include p-chloromethylstyrene, m-chloromethylstyrene, o-chloromethylstyrene, p-chloromethyl- α -methylstyrene, and the like. Specific examples of the unsaturated amide containing chlorine atom include N-chloromethyl (meth) acrylamide and the like. Specific examples of the chlorinated acetyl unsaturated monomer include 3- (hydroxychloroacetoxy) propyl allyl ether, p-vinylbenzyl chloroacetate, and the like.
These monomers containing at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom may be used singly or in combination, and the proportion thereof in the total monomer components is usually in the range of 0.01 to 10% by weight, preferably in the range of 0.05 to 8% by weight, more preferably in the range of 0.1 to 6% by weight, particularly preferably in the range of 0.5 to 5% by weight, most preferably in the range of 1 to 3% by weight.
The monomer other than the above (simply referred to as "other monomer" in the present invention) that can be used together with the above-described monomers as needed is not particularly limited as long as it can be copolymerized with the above-described monomer, and examples thereof include: aromatic vinyl monomers such as styrene, α -methylstyrene, divinylbenzene, etc.; ethylenically unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile; acrylamide monomers such as acrylamide and methacrylamide; olefin monomers such as ethylene, propylene, vinyl acetate, ethyl vinyl ether, butyl vinyl ether, and the like.
These other monomers may be used singly or in combination, and the ratio of these other monomers in the total monomer components is usually controlled in the range of 0 to 40% by weight, preferably in the range of 0 to 30% by weight, more preferably in the range of 0 to 20% by weight, particularly preferably in the range of 0 to 15% by weight, and most preferably in the range of 0 to 10% by weight.
< acrylic rubber >
The acrylic rubber constituting the acrylic rubber bag of the present invention has a reactive group selected from at least one of a carboxyl group, an epoxy group and a chlorine atom, and is preferably composed of a combination unit of at least one (meth) acrylic acid ester selected from an alkyl (meth) acrylate and an alkoxyalkyl (meth) acrylate, a monomer containing a reactive group selected from at least one of a carboxyl group, an epoxy group and a chlorine atom, and other monomers as required, and the respective proportions of these in the acrylic rubber are as follows: the binding unit derived from a (meth) acrylic acid ester of at least one selected from the group consisting of alkyl (meth) acrylates and alkoxyalkyl (meth) acrylates is generally in the range of 50 to 99.99% by weight, preferably in the range of 62 to 99.95% by weight, more preferably in the range of 74 to 99.9% by weight, particularly preferably in the range of 80 to 99.5% by weight, most preferably in the range of 87 to 99% by weight; the binding unit derived from a monomer containing at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom is usually in the range of 0.01 to 10% by weight, preferably in the range of 0.05 to 8% by weight, more preferably in the range of 0.1 to 6% by weight, particularly preferably in the range of 1 to 3% by weight; the bonding units from the other monomers are generally in the range from 0 to 40% by weight, preferably in the range from 0 to 30% by weight, more preferably in the range from 0 to 20% by weight, particularly preferably in the range from 0 to 15% by weight, most preferably in the range from 0 to 10% by weight. When the monomer composition of the acrylic rubber is within this range, the acrylic rubber bag is preferred because of a high balance of properties such as short-time crosslinkability, compression set resistance, weather resistance, heat resistance, and oil resistance.
The weight average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber package of the present invention is not particularly limited, and is usually 100 ten thousand or more, preferably 120 ten thousand or more, more preferably 150 ten thousand or more, in terms of absolute molecular weight measured by GPC-MALS method using dimethylformamide as an eluting solvent. When the weight average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber bag of the present invention is too small, strength characteristics and compression set characteristics are poor, which is not preferable. The weight average molecular weight (Mw) of the acrylic rubber of the present invention is usually in the range of 100 to 350 tens of thousands, preferably 120 to 300 tens of thousands, more preferably 130 to 300 tens of thousands, particularly preferably 150 to 250 tens of thousands, and most preferably 190 to 210 tens of thousands, and in this case, the roll processability, strength characteristics and compression set resistance of the acrylic rubber bag are highly balanced and therefore preferable.
The number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber package of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, but the absolute molecular weight measured by the GPC-MALS method using a dimethylformamide-based solvent as an eluting solvent is usually in the range of 10 to 50 tens of thousands, preferably in the range of 20 to 48 tens of thousands, more preferably in the range of 25 to 45 tens of thousands, particularly preferably in the range of 30 to 40 tens of thousands, most preferably in the range of 35 to 40 tens of thousands, and in this case, the roll processability, strength characteristics and compression set resistance characteristics of the acrylic rubber package are highly balanced and therefore preferable.
The z-average molecular weight (Mz) of the acrylic rubber constituting the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and the roll processability, strength characteristics and compression set resistance of the acrylic rubber bag are highly balanced, and therefore, it is preferable that the absolute molecular weight in the high molecular weight region is usually in the range of 150 to 600 tens of thousands, preferably in the range of 200 to 500 tens of thousands, more preferably in the range of 250 to 450 tens of thousands, and particularly preferably in the range of 300 to 400 tens of thousands, as measured by GPC-MALS method using a dimethylformamide-based solvent as an eluting solvent.
The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber package of the present invention is 3.4 or more, preferably 3.5 or more, more preferably 3.6 or more, still more preferably 3.7 or more, particularly preferably 3.8 or more, and most preferably 4 or more, in terms of absolute molecular weight distribution measured by GPC-MALS method using dimethylformamide-based solvent as eluting solvent. When the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber of the present invention is too small, the roll processability of the acrylic rubber bag is poor, and thus it is not preferable. The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber bag of the present invention is usually in the range of 3.7 to 6.5, preferably in the range of 3.8 to 6.2, more preferably in the range of 4 to 6, particularly preferably in the range of 4.5 to 5.7, most preferably in the range of 4.7 to 5.5, and in this case, the roll processability of the acrylic rubber bag, the strength characteristics at the time of crosslinking, and the compression set resistance can be highly balanced, and therefore, it is preferable.
The ratio (Mz/Mw) of the z-average molecular weight (Mz) to the weight-average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and it is preferable that the acrylic rubber bag has a high balance in processability and strength characteristics and can alleviate physical property changes upon storage, in terms of absolute molecular weight distribution in a side high molecular weight region measured by GPC-MALS method using dimethylformamide-based solvent as an eluting solvent, usually in the range of 1.3 to 3, preferably in the range of 1.4 to 2.7, more preferably in the range of 1.5 to 2.5, particularly preferably in the range of 1.8 to 2, most preferably in the range of 1.8 to 1.95.
The dimethylformamide-based solvent which can be used as the measurement solvent in the GPC-MALS method is not particularly limited as long as it is composed mainly of dimethylformamide, and for example, 100% dimethylformamide or a solvent in which the ratio of dimethylformamide in the dimethylformamide-based solvent is 90% by weight, preferably 95% by weight, and more preferably 97% by weight or more can be used. The compound to be added to dimethylformamide is not particularly limited, and in the present invention, a solution in which lithium chloride and 37% concentrated hydrochloric acid are added to dimethylformamide, respectively, so that the concentration of lithium chloride is 0.05mol/L and the concentration of hydrochloric acid is 0.01% is particularly preferable.
The glass transition temperature (Tg) of the acrylic rubber constituting the acrylic rubber bag of the present invention may be appropriately selected depending on the purpose of use of the acrylic rubber, and is usually 20 ℃ or lower, preferably 10 ℃ or lower, more preferably 0 ℃ or lower, and in this case, processability and cold resistance are excellent, and therefore, it is preferable. The lower limit of the glass transition temperature (Tg) of the acrylic rubber is not particularly limited, but is usually-80℃or higher, preferably-60℃or higher, more preferably-40℃or higher. The oil resistance and heat resistance of the acrylic rubber bag can be further improved by setting the glass transition temperature to the lower limit or more, and the processability, crosslinkability and cold resistance can be further improved by setting the glass transition temperature to the upper limit or less.
< acrylic rubber bag >
The acrylic rubber bag of the present invention is characterized by having at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom, preferably being formed of the above acrylic rubber, and having an insoluble methyl ethyl ketone component content of 50 wt% or less and an ash content of 0.4 wt% or less.
The amount of the acrylic rubber in the acrylic rubber bag of the present invention is not particularly limited, but is usually 90% by weight or more, preferably 95% by weight or more, more preferably 98% by weight, and still more preferably 99% by weight or more. The amount of acrylic rubber in the acrylic rubber bag of the present invention is approximately calculated as the value obtained by subtracting the ash amount from the weight of the acrylic rubber bag.
The amount of insoluble components in methyl ethyl ketone in the acrylic rubber bag of the present invention is preferably 50 wt% or less, more preferably 30 wt% or less, still more preferably 15 wt% or less, particularly preferably 10 wt% or less, and most preferably 5 wt% or less, and in this case, workability in kneading such as banbury is highly improved.
The value when the amount of the insoluble component of methyl ethyl ketone at any 20 points of the acrylic rubber bag of the present invention is measured is not particularly limited, but it is preferable that all points 20 are within the range of (average value.+ -. 5) wt%, and preferably all points 20 are within the range of (average value.+ -. 3) wt%, because there is no variation in processability, and the physical properties of the rubber composition and the crosslinked rubber product are stabilized. Further, when the value of the methyl ethyl ketone insoluble content at any 20 points of the acrylic rubber bag of the present invention is measured, that the values of all 20 points are within the range of ±5 of the average value means that the measured values of all 20 points of the methyl ethyl ketone insoluble content are within the range of (average value-5) to (average value +5) wt%, for example, when the average value of the measured values of the methyl ethyl ketone insoluble content is 20 wt%, the measured values of all 20 points are within the range of 15 to 25 wt%.
The acrylic rubber bag of the present invention is preferably an acrylic rubber bag obtained by melt-kneading and drying an aqueous pellet produced in a coagulation reaction in a state in which water is substantially removed (water content of less than 1% by weight) by a screw type biaxial extrusion dryer, and in this case, the banbury processability and strength characteristics are highly balanced.
The ash content of the acrylic rubber bag of the present invention is preferably 0.4 wt% or less, more preferably 0.3 wt% or less, still more preferably 0.2 wt% or less, still more preferably 0.18 wt% or less, particularly preferably 0.15 wt% or less, and most preferably 0.13 wt% or less, and when the ash content is within this range, the water resistance, strength characteristics, and workability of the acrylic rubber bag are highly balanced.
The lower limit of the ash content of the acrylic rubber bag of the present invention is not particularly limited, and is appropriately selected depending on the purpose of use, but is usually 0.0001 wt% or more, preferably 0.0005 wt% or more, more preferably 0.001 wt% or more, still more preferably 0.003 wt% or more, particularly preferably 0.005 wt% or more, and most preferably 0.01 wt% or more, and in this case, the metal adhesion of the rubber is reduced and the handleability is excellent, and therefore, the acrylic rubber bag is preferable.
The ash content of the acrylic rubber bag of the present invention at a high balance of water resistance, strength characteristics, workability and handling property is usually in the range of 0.0001 to 0.4% by weight, preferably in the range of 0.0005 to 0.3% by weight, more preferably in the range of 0.001 to 0.2% by weight, still more preferably in the range of 0.003 to 0.18% by weight, particularly preferably in the range of 0.005 to 0.15% by weight, most preferably in the range of 0.01 to 0.13% by weight.
The total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash of the acrylic rubber bag of the present invention is not particularly limited, and is preferably 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more, since the water resistance of the acrylic rubber is highly improved at this time, which is appropriately selected according to the purpose of use. In addition, when the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash of the acrylic rubber of the present invention falls within this range, the metal adhesion is reduced and the handleability is excellent, and therefore, it is preferable.
The total amount of magnesium and phosphorus in ash of the acrylic rubber bag of the present invention is not particularly limited, and is appropriately selected depending on the purpose of use, but is usually 30% by weight or more, preferably 50% by weight or more, more preferably 70% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more, and in this case, the water resistance, strength characteristics, and workability of the acrylic rubber are highly balanced and therefore preferable. When the total amount of magnesium and phosphorus in the ash of the acrylic rubber of the present invention falls within this range, the metal adhesion is reduced and the handleability is excellent, which is preferable.
The amount of magnesium in ash of the acrylic rubber bag of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, and is usually 10% by weight or more, preferably in the range of 15 to 60% by weight, more preferably in the range of 20 to 50% by weight, particularly preferably in the range of 25 to 45% by weight, and most preferably in the range of 30 to 40% by weight.
The amount of phosphorus in the ash of the acrylic rubber bag of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, and is usually 10% by weight or more, preferably in the range of 20 to 90% by weight, more preferably in the range of 30 to 80% by weight, particularly preferably in the range of 40 to 70% by weight, and most preferably in the range of 50 to 60% by weight.
The ratio of magnesium to phosphorus ([ Mg ]/[ P ]) in ash of the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually in the range of 0.4 to 2.5, preferably in the range of 0.45 to 1.2, more preferably in the range of 0.45 to 1, particularly preferably in the range of 0.5 to 0.8, most preferably in the range of 0.55 to 0.7, and in this case, the water resistance, strength characteristics and workability of the acrylic rubber are highly balanced and therefore preferable.
The ash in the acrylic rubber bag is mainly derived from an emulsifier used for emulsifying a monomer component and performing emulsion polymerization, and a coagulant used for coagulating an emulsion polymerization liquid, and the total ash amount, the content of magnesium and phosphorus in the ash, and the like are not only dependent on the conditions of the emulsion polymerization step and the coagulation step, but also vary depending on the conditions of the subsequent steps.
The acrylic rubber bag of the present invention preferably uses an anionic emulsifier, a cationic emulsifier or a nonionic emulsifier as an emulsifier in emulsion polymerization described later, and more preferably uses a phosphate or sulfate, and in this case, in addition to water resistance and strength characteristics, mold releasability and workability can be improved to a high degree. The water resistance of the acrylic rubber bag is mainly related to the ash content in the acrylic rubber and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash, and the use of the above-described emulsifier is preferable because the water resistance, strength characteristics, mold releasability and workability of the acrylic rubber bag can be further highly balanced.
The acrylic rubber bag of the present invention preferably uses a metal salt as a coagulant to be described later, and preferably uses an alkali metal salt or a metal salt of group 2 of the periodic table, and in this case, in addition to water resistance and strength characteristics, mold releasability and workability can be improved to a high degree. The water resistance of the acrylic rubber bag is mainly related to the ash content in the acrylic rubber and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash, and the use of the above-described coagulant is preferable because the water resistance, strength characteristics, mold releasability and workability of the acrylic rubber bag are more highly balanced.
The complex viscosity ([ eta ]60 ℃) of the acrylic rubber bag of the present invention at 60℃is not particularly limited, and is suitably selected depending on the purpose of use, but is usually not more than 15000[ Pa.s ], preferably in the range of 1000 to 10000[ Pa.s ], more preferably in the range of 2000 to 5000[ Pa.s ], particularly preferably in the range of 2500 to 4000[ Pa.s ], most preferably in the range of 2500 to 3000[ Pa.s ], and in this case, the processability, oil resistance and shape retention are excellent, and therefore, the acrylic rubber bag is preferable.
The complex viscosity (. Eta.100 ℃) of the acrylic rubber bag of the present invention at 100℃is not particularly limited, and it is preferable that the complex viscosity be appropriately selected depending on the purpose of use, and it is usually in the range of 1500 to 6000[ Pa.s ], preferably in the range of 2000 to 5000[ Pa.s ], more preferably in the range of 2300 to 4000[ Pa.s ], particularly preferably in the range of 2500 to 3500[ Pa.s ], and most preferably in the range of 2500 to 3000[ Pa.s ], because the processability, oil resistance and shape retention are excellent.
The ratio of the complex viscosity at 100 ℃ ([ eta ]100 ℃) to the complex viscosity at 60 ℃ ([ eta ]60 ℃) ([ eta ]100 ℃/[ eta ]60 ℃) of the acrylic rubber package of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually 0.5 or more, preferably 0.6 or more, more preferably 0.7 or more, particularly preferably 0.8 or more, and most preferably 0.83 or more. In addition, the ratio of the complex viscosity at 100 ℃ ([ eta ]100 ℃) to the complex viscosity at 60 ℃ ([ eta ]60 ℃) ([ eta ]100 ℃/[ eta ]60 ℃) of the acrylic rubber bag of the present invention is usually in the range of 0.5 to 0.99, preferably in the range of 0.6 to 0.98, more preferably in the range of 0.7 to 0.97, particularly preferably in the range of 0.8 to 0.96, most preferably in the range of 0.85 to 0.95, and in this case, the processability, oil resistance and shape retention are highly balanced, and therefore preferred.
The water content of the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually less than 1% by weight, preferably 0.8% by weight or less, more preferably 0.6% by weight or less, and in this case, the vulcanization characteristics of the acrylic rubber bag are optimal, and the characteristics such as heat resistance and strand-like water resistance are highly improved, and therefore, it is preferable.
The pH of the acrylic rubber bag of the present invention is not particularly limited, and is preferably selected appropriately according to the purpose of use, and is usually 6 or less, preferably in the range of 2 to 6, more preferably in the range of 2.5 to 5.5, and most preferably in the range of 3 to 5, in which case the storage stability of the acrylic rubber bag is highly improved.
The Mooney viscosity (ML1+4, 100 ℃) of the acrylic rubber bag of the present invention is not particularly limited, and is preferably selected appropriately according to the purpose of use, and is usually in the range of 10 to 150, preferably 20 to 100, more preferably 25 to 70, and in this case, the processability and strength characteristics of the acrylic rubber bag are highly balanced.
The specific gravity of the acrylic rubber bag of the present invention is not particularly limited, but is usually 0.7 or more, preferably 0.75 or more, more preferably 0.8 or more, still more preferably 0.9 or more, particularly preferably 0.95 or more, and most preferably 1 or more, and in this case, air is hardly present in the interior, and the storage stability is excellent, so that it is preferable. The specific gravity of the acrylic rubber bag of the present invention is preferably in the range of usually 0.7 to 1.6, preferably 0.8 to 1.5, more preferably 0.9 to 1.4, particularly preferably 0.95 to 1.3, and most preferably 1.0 to 1.2, because the productivity, storage stability, and crosslinking characteristic stability of the crosslinked product are highly balanced. When the specific gravity of the acrylic rubber bag is too small, it means that the amount of air in the acrylic rubber is large, which has a large influence on the storage stability including oxidative deterioration and the like, and is not preferable.
The specific gravity of the acrylic rubber bag of the present invention is the specific gravity of the mass divided by the volume including voids, that is, the specific gravity of the mass divided by the buoyancy measured in air, and is the specific gravity measured by the a method generally measured according to JIS K6268 crosslinked rubber-density measurement.
The acrylic rubber bag of the present invention is preferably an acrylic rubber bag obtained by drying the aqueous pellets produced in the coagulation reaction by a screw type biaxial extrusion dryer under reduced pressure or melt kneading and drying under reduced pressure, and is particularly excellent in characteristics such as storage stability, roll processability and strength characteristics and is highly balanced.
The size of the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and the appropriate width is usually in the range of 100 to 800mm, preferably in the range of 200 to 500mm, more preferably in the range of 250 to 450mm, and the length is usually in the range of 300 to 1200mm, preferably in the range of 400 to 1000mm, more preferably in the range of 500 to 800mm, and the height (thickness) is usually in the range of 50 to 500mm, preferably in the range of 100 to 300mm, more preferably in the range of 150 to 250 mm. The shape of the acrylic rubber bag of the present invention is not limited, and may be appropriately selected depending on the purpose of use of the acrylic rubber bag, and in many cases, a rectangular parallelepiped shape is preferable.
< method for producing acrylic rubber bag >
The method for producing the acrylic rubber bag is not particularly limited, and for example, the acrylic rubber bag can be easily produced by a method comprising the steps of: an emulsion polymerization step of emulsifying an acrylic rubber monomer component containing a monomer having at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom with pure water and an emulsifier, initiating polymerization in the presence of a redox catalyst comprising an inorganic radical generator and a reducing agent, adding a chain transfer agent in a batch manner during the polymerization, and continuing the polymerization to obtain an emulsion polymerization solution; a coagulation step of adding the emulsion polymerization liquid obtained to the stirred coagulation liquid to coagulate the emulsion polymerization liquid, thereby producing water-containing pellets; a washing step of washing the produced hydrous pellets with hot water; a dehydration step of dehydrating the washed aqueous pellets; a drying step of drying the dehydrated aqueous pellets to less than 1 wt%; and a rubber coating step of coating the dried rubber with rubber.
(monomer component)
The monomer component used in the present invention, which contains a monomer containing a reactive group selected from at least one of a carboxyl group, an epoxy group, and a chlorine atom, is the same as the examples and preferred ranges of the monomer component already described. As already described, the amount of the monomer component used may be appropriately selected so that the composition of the acrylic rubber of the present invention becomes the composition described above in emulsion polymerization.
(emulsifier)
The emulsifier used in the present invention is not particularly limited, and examples thereof include anionic emulsifiers, cationic emulsifiers, nonionic emulsifiers, and the like, and anionic emulsifiers are preferable.
The anionic emulsifier is not particularly limited, and examples thereof include: salts of fatty acids such as myristic acid, palmitic acid, oleic acid, and linolenic acid; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; sulfate salts such as sodium lauryl sulfate, phosphate salts such as polyoxyalkylene alkyl ether phosphate salts; alkyl sulfosuccinates, and the like. Among these anionic emulsifiers, phosphate salts and sulfate salts are preferable, phosphate salts are particularly preferable, and dibasic phosphate salts are most preferable, since the water resistance, strength characteristics, mold releasability and workability of the resulting acrylic rubber bag can be highly balanced. The phosphate and sulfate are preferably alkali metal salts of phosphate and sulfate, and more preferably sodium salts of phosphate and sulfate, and in this case, the water resistance, strength characteristics, mold release properties, and workability of the resulting acrylic rubber bag can be highly balanced, and thus are preferable.
The dibasic phosphate is not particularly limited as long as it can be used as an emulsifier in emulsion polymerization, and examples thereof include alkoxypolyoxyalkylene phosphate and alkylphenoxypolyoxyalkylene phosphate, and among these, metal salts thereof are preferable, alkali metal salts thereof are more preferable, and sodium salts thereof are most preferable.
Examples of the alkoxypolyoxyalkylene phosphate include alkoxypolyoxyethylene phosphate and alkoxypolyoxypropylene phosphate, and among these, alkoxypolyoxyethylene phosphate is preferable.
As specific examples of the alkoxypolyoxyethylene phosphate salt, there may be mentioned octyloxydioxyethylene phosphate, octyloxytrioxyethylene phosphate, octyloxytetraethylene phosphate, decyloxy tetraethylene phosphate, dodecyloxytetraethylene phosphate, tridecyloxytetraethylene phosphate, tetradecyloxy tetraethylene phosphate, hexadecyloxy tetraethylene phosphate, octadecyl tetraethylene phosphate, octyloxypentaethylene phosphate, decyloxy pentaethylene phosphate, dodecyloxypentaethylene phosphate, tridecyloxypentaethylene phosphate, tetradecyloxy pentaethylene phosphate, hexadecyloxy pentaethylene phosphate, octadecyl pentaethylene phosphate, octyloxyhexaethylene phosphate, decyloxy hexaethylene phosphate, dodecyloxyhexaethylene phosphate, tridecyloxyhexaethylene phosphate, tetradecyloxy hexaethylene phosphate, hexadecyloxy hexaethylene phosphate, octadecyl hexaethylene phosphate, octooxyoctaethylene phosphate, decaoxyoctaethylene phosphate, dodecanoxyoctaethylene phosphate, tridecyloxyoctaethylene phosphate, tetradecyloxy octaethylene phosphate, and octaalkoxyoctaethylene phosphate, especially preferred among these are sodium salts of these.
Specific examples of the alkoxypolyoxypropylene phosphate include octyloxybispropylenephosphate, octyloxybropylenephosphate, decyloxy tetrapropylenephosphate, dodecyloxypropylenephosphate, tridecyloxypropylenephosphate, tetradecyloxy tetrapropylenephosphate, hexadecyloxy tetrapropylenephosphate, octadecyloxypropylenephosphate, octyloxypropylenephosphate, decyloxy pentapropylenephosphate, dodecyloxypropylenephosphate, tridecyloxypropylenephosphate, tetradecyloxy pentapropylenephosphate, hexadecyloxy pentapropylenephosphate, octadecyloxypropylenephosphate, octyloxypropylenephosphate, decyloxy hexaoxypropylenephosphate, dodecyloxypropylenephosphate, tridecyloxypropylenephosphate, tetradecyloxy hexaoxypropylenephosphate, hexadecyloxy hexaropylenephosphate, hexadecyloxy octaoxypropylenephosphate, dodecyloxypropylenephosphate, tridecyloxypropylenephosphate, octaalkoxyoxypropylenephosphate, octaalkoxyl octaropylenephosphate, octaalkoxyl oxypropylenephosphate, and octaalkoxyropylenephosphate, and the like, and their metal salts are particularly preferred among them.
Specific examples of the alkylphenoxy polyoxyalkylene phosphate include alkylphenoxy polyoxyethylene phosphate and alkylphenoxy polyoxypropylene phosphate, and among these, alkylphenoxy polyoxyethylene phosphate is preferred.
Specific examples of the alkylphenoxypolyoxyethylene phosphate salt include metal salts such as methylphenoxy tetraoxyethylene phosphate, ethylphenoxytetraoxyethylene phosphate, butylphenoxy tetraoxyethylene phosphate, hexylphenoxy tetraoxyethylene phosphate, nonylphenoxy tetraoxyethylene phosphate, dodecylphenoxy tetraoxyethylene phosphate, octadecylphenoxy tetraoxyethylene phosphate, methylphenoxy pentaoxyethylene phosphate, ethylphenoxypentaoxyethylene phosphate, butylphenoxy pentaoxyethylene phosphate, hexylphenoxy pentaoxyethylene phosphate, nonylphenoxy pentaoxyethylene phosphate, dodecylphenoxy pentaoxyethylene phosphate, methylphenoxy hexaoxyethylene phosphate, ethylphenoxyhexaoxyethylene phosphate, butylphenoxy hexaoxyethylene phosphate, hexylphenoxy hexaoxyethylene phosphate, nonylphenoxy hexaoxyethylene phosphate, ethylphenoxyoctaoxyethylene phosphate, butylphenoxy octaoxyethylene phosphate, hexylphenoxy octaoxyethylene phosphate, nonylphenoxy octaoxyethylene phosphate, dodecylphenoxy octaoxyethylene phosphate, and the like, and sodium salts thereof are particularly preferred.
Specific examples of the alkylphenoxypolyoxypropylene phosphate include metal salts such as methylphenoxy tetrapropoxy phosphate, ethylphenoxytetrapropoxy phosphate, butylphenoxy tetrapropoxy phosphate, hexylphenoxy tetrapropoxy phosphate, nonylphenoxy tetrapropoxy phosphate, dodecylphenoxy tetrapropoxy phosphate, methylphenoxy pentapropoxy phosphate, ethylphenoxy pentapropoxy phosphate, butylphenoxy pentapropoxy phosphate, hexylphenoxy pentapropoxy phosphate, nonylphenoxy pentapropoxy phosphate, dodecylphenoxy pentapropoxy phosphate, methylphenoxy hexaoxypropoxy phosphate, ethylphenoxy hexaoxypropoxy phosphate, butylphenoxy hexaoxyprop phosphate, hexylphenoxy hexaoxyprop phosphate, nonylphenoxy hexaoxyprop phosphate, dodecylphenoxy hexaoxyprop phosphate, methylphenoxy octaoxyprop phosphate, ethylphenoxy octaoxyprop phosphate, butylphenoxy octaoxyprop phosphate, hexylphenoxy octaoxyprop phosphate, nonylphenoxy octaoxyprop phosphate, dodecylphenoxy octaoxyprop phosphate, and the like, and alkali metal salts thereof are particularly preferred.
As the phosphate ester salt, a mono phosphate ester salt such as a sodium salt of di (alkoxypolyoxyalkylene) phosphate ester can be used alone or in combination with a 2-membered phosphate ester salt.
Examples of the sulfate salt include sodium lauryl sulfate, potassium lauryl sulfate, ammonium lauryl sulfate, sodium myristyl sulfate, sodium polyoxyethylene alkyl sulfate, and sodium polyoxyethylene alkylaryl sulfate, and sodium lauryl sulfate is particularly preferred.
Examples of the cationic emulsifier include alkyl trimethyl ammonium chloride, dialkyl ammonium chloride, benzyl ammonium chloride, and the like.
Examples of the nonionic emulsifier include: polyoxyalkylene fatty acid esters such as polyoxyethylene stearate; polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether; polyoxyalkylene alkylphenol ethers such as polyoxyethylene nonylphenyl ether; the polyoxyethylene sorbitol alkyl ester is preferably a polyoxyalkylene alkyl ether or a polyoxyalkylene alkylphenol ether, and more preferably a polyoxyethylene alkyl ether or a polyoxyethylene alkylphenol ether.
These emulsifiers may be used alone or in combination of two or more, and the amount thereof is usually in the range of 0.01 to 10 parts by weight, preferably in the range of 0.1 to 5 parts by weight, more preferably in the range of 1 to 3 parts by weight, relative to 100 parts by weight of the monomer component.
The method (mixing method) for mixing the monomer component, water and emulsifier may be a conventional method, and examples thereof include a method of stirring the monomer, emulsifier and water using a stirrer such as a homogenizer or a disk turbine (disk turbine). The amount of water to be used is usually in the range of 1 to 1000 parts by weight, preferably in the range of 5 to 500 parts by weight, more preferably in the range of 4 to 300 parts by weight, particularly preferably in the range of 3 to 150 parts by weight, most preferably in the range of 20 to 80 parts by weight, relative to 100 parts by weight of the monomer component.
(inorganic radical generator)
The polymerization catalyst used in the present invention is characterized by using a redox catalyst comprising an inorganic radical generator and a reducing agent. In particular, the use of an inorganic radical generator is preferable because the workability of the roll or the like of the produced acrylic rubber bag can be improved to a high degree.
The inorganic radical generator is not particularly limited as long as it is an inorganic radical generator generally used in emulsion polymerization, and examples thereof include persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate, and hydrogen peroxide, and among these, persulfates are preferable, potassium persulfate and ammonium persulfate are more preferable, and potassium persulfate is particularly preferable.
These inorganic radical generators may be used singly or in combination of two or more kinds, and the amount thereof is usually in the range of 0.0001 to 5 parts by weight, preferably in the range of 0.0005 to 1 part by weight, more preferably in the range of 0.001 to 0.25 part by weight, particularly preferably in the range of 0.01 to 0.21 part by weight, most preferably in the range of 0.1 to 0.2 part by weight, relative to 100 parts by weight of the monomer component.
(reducing agent)
The reducing agent used in the present invention is not particularly limited as long as it is a reducing agent that can be used in emulsion polymerization in general, and it is preferable to use at least two reducing agents in combination with a metal ion compound in a reduced state and a reducing agent other than the metal ion compound, because the banbury processability, roll processability and strength characteristics of the resulting acrylic rubber bag can be further highly balanced.
The metal ion compound in the reduced state is not particularly limited, and examples thereof include ferrous sulfate, sodium iron hexamethylenediamine tetraacetate, cuprous naphthenate, and the like, and among these, ferrous sulfate is preferable. These metal ion compounds in a reduced state may be used singly or in combination, and the amount thereof is usually in the range of 0.000001 to 0.01 parts by weight, preferably in the range of 0.00001 to 0.001 parts by weight, more preferably in the range of 0.00005 to 0.0005 parts by weight, relative to 100 parts by weight of the monomer component.
The reducing agent other than the metal ion compound in the reduced state used in the present invention is not particularly limited, and examples thereof include: ascorbic acid or its salts such as ascorbic acid, sodium ascorbate, potassium ascorbate, etc.; erythorbic acid or salts thereof such as erythorbic acid, sodium erythorbate, and potassium erythorbate; sulfinate salts such as sodium hydroxymethanesulfinate; sulfite such as sodium sulfite, potassium sulfite, sodium bisulfite, sodium aldehyde bisulfite, and potassium bisulfite; metabisulfites such as sodium metabisulfite, potassium metabisulfite, sodium metabisulfite, potassium metabisulfite and the like; thiosulfate such as sodium thiosulfate and potassium thiosulfate; phosphorous acid or salts thereof such as phosphorous acid, sodium phosphite, potassium phosphite, sodium hydrogen phosphite, potassium hydrogen phosphite, etc.; pyrophosphorous acid or salts thereof such as pyrophosphorous acid, sodium pyrophosphate, potassium pyrophosphate, sodium hydrogen pyrophosphate, potassium hydrogen pyrophosphate, etc.; sodium formaldehyde sulfoxylate, and the like. Among these, ascorbic acid or a salt thereof, sodium formaldehyde sulfoxylate, and the like are preferable, and ascorbic acid or a salt thereof is particularly preferable.
These reducing agents other than the metal ion compound in the reduced state may be used singly or in combination of two or more, and the amount thereof is usually in the range of 0.001 to 1 part by weight, preferably in the range of 0.005 to 0.5 part by weight, more preferably in the range of 0.01 to 0.1 part by weight, relative to 100 parts by weight of the monomer component.
The preferred combination of the metal ion compound in the reduced state with a reducing agent other than it is a combination of ferrous sulfate with ascorbic acid or a salt thereof and/or sodium formaldehyde sulfoxylate, more preferably a combination of ferrous sulfate with ascorbic acid or a salt thereof. In this case, the amount of the ferrous sulfate to be used is usually in the range of 0.000001 to 0.01 parts by weight, preferably in the range of 0.00001 to 0.001 parts by weight, more preferably in the range of 0.00005 to 0.0005 parts by weight, relative to 100 parts by weight of the monomer component, and the amount of the ascorbic acid or a salt thereof and/or sodium formaldehyde sulfoxylate to be used is usually in the range of 0.001 to 1 part by weight, preferably in the range of 0.005 to 0.5 parts by weight, more preferably in the range of 0.01 to 0.1 part by weight, relative to 100 parts by weight of the monomer component.
The amount of water used in the emulsion polymerization may be only that used in the emulsification of the monomer component, or may be adjusted so that the amount of water used is usually in the range of 10 to 1000 parts by weight, preferably in the range of 50 to 500 parts by weight, more preferably in the range of 80 to 400 parts by weight, and most preferably in the range of 100 to 300 parts by weight, relative to 100 parts by weight of the monomer component used for the polymerization.
The emulsion polymerization may be carried out by a conventional method, and may be carried out in any of batch, semi-batch, and continuous modes. The polymerization temperature and polymerization time are not particularly limited, and may be appropriately selected depending on the kind of the polymerization initiator used, and the like. The polymerization time is usually 0.5 to 100 hours, preferably 1 minute to 10 hours.
The emulsion polymerization is exothermic, and if not controlled, the temperature is increased to shorten the polymerization reaction, but in the present invention, the emulsion polymerization temperature is usually controlled to 35℃or less, preferably 0 to 35℃and more preferably 5 to 30℃and particularly preferably 10 to 25℃and the strength characteristics of the produced acrylic rubber bag and the processability in kneading such as Banbury are preferably highly balanced.
(post addition of chain transfer agent)
The present invention is characterized in that it is preferable to be able to produce an acrylic rubber having a high molecular weight component and a low molecular weight component separated from each other by adding the acrylic rubber in a batch manner during the polymerization without adding a chain transfer agent at the beginning, and the strength characteristics of the produced acrylic rubber package are highly balanced with the processability during kneading with a roll or the like.
The chain transfer agent to be used is not particularly limited as long as it is a chain transfer agent generally used in emulsion polymerization, and for example, a thiol compound can be preferably used.
As the thiol compound, an alkyl thiol compound having 2 to 20 carbon atoms, preferably an alkyl thiol compound having 5 to 15 carbon atoms, more preferably an alkyl thiol compound having 6 to 14 carbon atoms can be used.
The alkyl thiol compound may be any of an n-alkyl thiol compound, a secondary alkyl thiol compound, and a tertiary alkyl thiol compound, and is preferably an n-alkyl thiol compound or a tertiary alkyl thiol compound, and more preferably an n-alkyl thiol compound, and in this case, the effect of the chain transfer agent can be stably exhibited, and the processability of the produced acrylic rubber bag such as a roller can be highly improved, which is preferable.
Specific examples of the alkyl thiol compound include n-pentyl thiol, n-hexyl thiol, n-heptyl thiol, n-octyl thiol, n-decyl thiol, n-dodecyl thiol, n-tridecyl thiol, n-tetradecyl thiol, n-hexadecyl thiol, n-octadecyl thiol, sec-pentyl thiol, sec-hexyl thiol, sec-heptyl thiol, sec-octyl thiol, zhong Guiji thiol, sec-dodecyl thiol, sec-tridecyl thiol, sec-tetradecyl thiol, sec-hexadecyl thiol, sec-octadecyl thiol, tert-amyl thiol, tert-hexyl thiol, tert-heptyl thiol, tert-octyl thiol, tert-decyl thiol, tert-dodecyl thiol, tert-tridecyl thiol, tert-tetradecyl thiol, tert-hexadecyl thiol, tert-octadecyl thiol, and the like, preferably n-octyl thiol, n-dodecyl thiol, tert-dodecyl thiol, more preferably n-octyl thiol, and n-dodecyl thiol.
These chain transfer agents can be used either individually or in combination of two or more. The amount of the chain transfer agent used is not particularly limited, but is preferably in the range of usually 0.0001 to 1 part by weight, preferably 0.0005 to 0.5 part by weight, more preferably 0.001 to 0.5 part by weight, particularly preferably 0.005 to 0.1 part by weight, and most preferably 0.01 to 0.06 part by weight, based on 100 parts by weight of the monomer component, and in this case, the strength characteristics of the produced acrylic rubber bag are highly balanced with the roll processability.
The present invention is characterized in that the high molecular weight component and the low molecular weight component of the obtained acrylic rubber can be produced by adding the chain transfer agent in a batch manner during the polymerization without adding the chain transfer agent at the beginning of the polymerization, and the strength characteristics of the acrylic rubber bag and the processability of the roll or the like can be highly balanced by adjusting the molecular weight distribution to a specific range.
The number of times of post-addition of the chain transfer agent in batches is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually 1 to 5 times, preferably 2 to 4 times, more preferably 2 to 3 times, and particularly preferably 2 times, and in this case, the strength characteristics of the produced acrylic rubber bag can be highly balanced with the workability of rolls and the like, and is therefore preferable.
The timing of starting the batch-wise post-addition of the chain transfer agent is not particularly limited and may be appropriately selected depending on the purpose of use, and is usually in the range of 20 minutes after the initiation of polymerization, preferably 30 minutes after the initiation of polymerization, more preferably 30 to 200 minutes after the initiation of polymerization, particularly preferably 35 to 150 minutes after the initiation of polymerization, and most preferably 40 to 120 minutes, and in this case, the strength characteristics of the produced acrylic rubber bag can be highly balanced with the workability of rolls and the like, and is therefore preferable.
In the case where the chain transfer agent is added after being batched, the amount to be added per one time is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually in the range of 0.00005 to 0.5 parts by weight, preferably in the range of 0.0001 to 0.1 parts by weight, more preferably in the range of 0.0005 to 0.05 parts by weight, particularly preferably in the range of 0.001 to 0.03 parts by weight, most preferably in the range of 0.002 to 0.02 parts by weight, based on 100 parts by weight of the monomer component, and in this case, the strength characteristics of the produced acrylic rubber bag and the roll processability can be highly balanced, and thus are preferable.
The chain transfer agent is not particularly limited after the addition, and the polymerization reaction may be continued for usually 30 minutes or more, preferably 45 minutes or more, and more preferably 1 hour or more.
(post addition of reducing agent)
In the present invention, the reducing agent of the redox catalyst can be added after the polymerization process, and thus the strength characteristics of the produced acrylic rubber bag can be highly balanced with the processability of rolls and the like, and is preferable.
The reducing agent added later in the polymerization process is the same as the above-mentioned examples and preferable ranges of the reducing agent. In the present invention, as the reducing agent to be added later, ascorbic acid or a salt thereof is preferable.
The amount of the reducing agent to be added after the polymerization is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually in the range of 0.0001 to 1 part by weight, preferably in the range of 0.0005 to 0.5 part by weight, more preferably in the range of 0.001 to 0.5 part by weight, particularly preferably in the range of 0.005 to 0.1 part by weight, most preferably in the range of 0.01 to 0.05 part by weight, based on 100 parts by weight of the monomer component, and in this case, the productivity of the production of the acrylic rubber bag is excellent, and the strength characteristics and workability of the produced acrylic rubber bag can be highly balanced, and therefore, the production is preferable.
The reducing agent added later in the polymerization process may be added continuously or batchwise, preferably batchwise. The number of times when the reducing agent is added in the polymerization process after it is batchwise is not particularly limited, but is usually 1 to 5 times, preferably 1 to 3 times, more preferably 1 to 2 times.
When the reducing agent added later in the polymerization initiation and polymerization process is ascorbic acid or a salt thereof, the ratio of the amount of the initially added ascorbic acid or a salt thereof to the amount of the later added ascorbic acid or a salt thereof is not particularly limited, but is usually in the range of 1/9 to 8/2, preferably in the range of 2/8 to 6/4, more preferably in the range of 3/7 to 5/5, in terms of the weight ratio of "the initially added ascorbic acid or a salt thereof"/"the ascorbic acid or a salt thereof added after batchwise", and in this case, the productivity of the production of the acrylic rubber bag is excellent, and the strength characteristics and the workability of the produced acrylic rubber bag can be highly balanced, and therefore, it is preferable.
The timing of the post-addition of the reducing agent is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually in the range of 1 to 3 hours after the initiation of polymerization, preferably in the range of 1.5 to 2.5 hours after the initiation of polymerization, and in this case, the productivity of the production of the acrylic rubber bag is excellent, and the strength characteristics of the produced acrylic rubber bag can be highly balanced with the workability of rolls and the like, which is preferable.
In the case where the reducing agent is added after being added in portions, the amount to be added per one time is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually in the range of 0.00005 to 0.5 parts by weight, preferably in the range of 0.0001 to 0.1 parts by weight, more preferably in the range of 0.0005 to 0.05 parts by weight, and particularly preferably in the range of 0.001 to 0.03 parts by weight, based on 100 parts by weight of the monomer component, and in this case, the strength characteristics of the produced acrylic rubber package can be highly balanced with the workability of rolls and the like, and is therefore preferable.
The operation after the addition of the reducing agent is not particularly limited, and the polymerization reaction can be terminated after the polymerization reaction is continued for usually 30 minutes or more, preferably 45 minutes or more, and more preferably 1 hour or more.
The polymerization conversion rate of the emulsion polymerization is not particularly limited, but is usually 90% by weight or more, preferably 95% by weight or more, and in this case, the produced acrylic rubber bag is preferable because it is excellent in strength characteristics and free from odor of the monomer. At the termination of the polymerization, a polymerization terminator may be used.
(coagulation step)
The method for coagulation after emulsion polymerization is characterized in that the emulsion polymerization liquid obtained in emulsion polymerization is added to the stirred coagulation liquid to coagulate, and an aqueous pellet of the acrylic rubber is produced.
The solid content concentration of the emulsion polymerization liquid used in the coagulation reaction is not particularly limited, and is usually adjusted to a range of 5 to 50% by weight, preferably 10 to 45% by weight, and more preferably 20 to 40% by weight.
The coagulant of the coagulant liquid to be used is not particularly limited, and a metal salt can be generally used. The metal salt may be, for example, an alkali metal, a metal salt of group 2 of the periodic table, or other metal salt, and is preferably an alkali metal salt or a metal salt of group 2 of the periodic table, more preferably a metal salt of group 2 of the periodic table, and particularly preferably a magnesium salt, and in this case, the water resistance, strength characteristics, mold releasability, and workability of the resulting acrylic rubber bag can be highly balanced, and thus are preferable.
Examples of the alkali metal salt include: sodium salts such as sodium chloride, sodium nitrate, and sodium sulfate; potassium salts such as potassium chloride, potassium nitrate, and potassium sulfate; among these, sodium salts are preferable, and sodium chloride and sodium sulfate are particularly preferable.
Examples of the metal salt of group 2 of the periodic table include magnesium chloride, calcium chloride, magnesium nitrate, calcium nitrate, magnesium sulfate, and calcium chloride and magnesium sulfate are preferable.
Examples of the other metal salt include zinc chloride, titanium chloride, manganese chloride, iron chloride, cobalt chloride, nickel chloride, aluminum chloride, tin chloride, zinc nitrate, titanium nitrate, manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate, aluminum nitrate, tin nitrate, zinc sulfate, titanium sulfate, manganese sulfate, iron sulfate, cobalt sulfate, nickel sulfate, aluminum sulfate, and tin sulfate.
These coagulants may be used alone or in combination of two or more, and the amount thereof is usually in the range of 0.01 to 100 parts by weight, preferably in the range of 0.1 to 50 parts by weight, more preferably in the range of 1 to 30 parts by weight, relative to 100 parts by weight of the monomer component. When the coagulant is in this range, the acrylic rubber can be sufficiently coagulated, and when the acrylic rubber bag is crosslinked, compression set resistance and water resistance can be highly improved, which is preferable.
In the coagulation step of the present invention, it is preferable to significantly increase the cleaning efficiency and ash removal efficiency during dehydration by particularly concentrating the particle size of the produced aqueous aggregates in a specific region. The proportion of the produced aqueous pellet in the range of 710 μm to 6.7mm (6.7 mm excluding 710 μm) is not particularly limited, but is preferably 30% by weight or more, more preferably 50% by weight or more, still more preferably 60% by weight or more, particularly preferably 70% by weight or more, and most preferably 80% by weight or more, based on the total amount of the produced aqueous pellet, and in this case, the water resistance of the acrylic rubber bag can be significantly improved. The proportion of the produced aqueous pellet in the range of 710 μm to 4.75mm (4.75 mm excluding 710 μm) is not particularly limited, but is preferably 30% by weight or more, more preferably 50% by weight or more, still more preferably 60% by weight or more, particularly preferably 70% by weight or more, and most preferably 80% by weight or more, based on the total amount of the produced aqueous pellet, and in this case, the water resistance of the acrylic rubber bag can be significantly improved. Further, the proportion of the produced aqueous pellet in the range of 710 μm to 3.35mm (3.35 mm excluding 710 μm) is not particularly limited, but is usually 20% by weight or more, preferably 30% by weight or more, more preferably 40% by weight or more, particularly preferably 50% by weight or more, and most preferably 60% by weight or more relative to the total amount of the produced aqueous pellet, and in this case, the water resistance of the acrylic rubber bag can be significantly improved, and thus it is preferable.
The means for forming the particle size of the formed aqueous pellets in the above-described range is not particularly limited, and the method of contacting the emulsion polymerization liquid with the coagulant may be, for example, a method of adding the emulsion polymerization liquid to a stirred coagulant (aqueous coagulant solution) or a method of specifying the coagulant concentration of the coagulant, the number of stirring steps of the stirred coagulant, or the circumferential speed.
The coagulant to be used is usually used in the form of an aqueous solution, but the concentration of the coagulant in the aqueous solution is not particularly limited, and is usually 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more, and particularly preferably 1.5% by weight or more. The coagulant concentration of the coagulant is preferably in the range of 0.1 to 20% by weight, preferably in the range of 0.5 to 15% by weight, more preferably in the range of 1 to 10% by weight, and particularly preferably in the range of 1.5 to 5% by weight, because the particle size of the resulting aqueous aggregates can be uniformly concentrated in a specific region.
The temperature of the coagulating liquid is not particularly limited, but is usually 40℃or higher, preferably in the range of 40 to 90℃and more preferably in the range of 50 to 80℃and, in this case, uniform aqueous pellets are preferably produced.
The stirring number (rotation speed) of the stirred coagulation liquid, that is, the rotation speed of the stirring blade of the stirring device is not particularly limited, but is usually 100rpm or more, preferably 200rpm or more, more preferably in the range of 200 to 1000rpm, particularly preferably in the range of 300 to 900rpm, and most preferably in the range of 400 to 800 rpm.
Since the rotational speed is such that the particles of the produced aqueous pellets can be made small and uniform by stirring them vigorously to a certain extent, it is preferable that the rotational speed is not less than the above-mentioned lower limit, and that the production of pellets having excessively large and excessively small particle diameters can be suppressed, and that the rotational speed is not more than the above-mentioned upper limit, and that the coagulation reaction can be controlled more easily.
The peripheral speed of the stirred coagulation liquid, that is, the speed of the outer periphery of the stirring blade of the stirring device is not particularly limited, and the particle size of the resulting aqueous aggregates can be made small and uniform by stirring vigorously to a certain extent, and therefore, it is preferably usually 0.5m/s or more, preferably 1m/s or more, more preferably 1.5m/s or more, particularly preferably 2m/s or more, and most preferably 2.5m/s or more. On the other hand, the upper limit of the peripheral speed is not particularly limited, but is usually 50m/s or less, preferably 30m/s or less, more preferably 25m/s or less, and most preferably 20m/s or less, and in this case, the control of the solidification reaction is facilitated, and is therefore preferable.
By setting the above-mentioned conditions of the coagulation reaction (the addition method, the solid content concentration of the emulsion polymerization liquid, the concentration and temperature of the coagulation liquid, the rotational speed and peripheral speed of the coagulation liquid at the time of stirring, etc.) in a specific range, the shape and the pellet size of the produced aqueous pellets are uniform and concentrated, and the removal of the emulsifier and the coagulant at the time of washing and dehydration is markedly improved, and as a result, the water resistance and the storage stability of the produced acrylic rubber bag can be highly improved, which is preferable.
(cleaning step)
The cleaning step in the method for producing an acrylic rubber bag of the present invention is characterized by cleaning the aqueous pellet produced in the coagulation reaction with hot water.
The washing method is not particularly limited, and can be performed by mixing the produced aqueous pellets with a large amount of hot water.
The amount of hot water to be added for washing is not particularly limited, but is preferably 50 parts by weight or more, preferably 50 to 15000 parts by weight, more preferably 100 to 10000 parts by weight, and even more preferably 500 to 5000 parts by weight per 1 time of washing per 100 parts by weight of the monomer component, in which case the ash content in the acrylic rubber bag can be effectively reduced.
The temperature of the hot water to be used is not particularly limited, but is usually 40 ℃ or higher, preferably 40 to 100 ℃, more preferably 50 to 90 ℃, particularly preferably 60 to 80 ℃, and in this case, the cleaning efficiency can be significantly improved, and thus it is preferable. When the temperature of the water to be used is not less than the lower limit, the emulsifier and the coagulant are separated from the aqueous pellet, and the cleaning efficiency is further improved.
The washing time is not particularly limited, and is usually in the range of 1 to 120 minutes, preferably in the range of 2 to 60 minutes, more preferably in the range of 3 to 30 minutes.
The number of times of washing (water washing) is not particularly limited, and is usually 1 to 10 times, preferably 1 to 5 times, more preferably 2 to 3 times. In addition, from the viewpoint of reducing the residual amount of the coagulant in the finally obtained acrylic rubber bag, it is desirable that the number of times of washing is large, but by setting the shape of the aqueous aggregates and the particle size of the aqueous aggregates to the specific ranges as described above and/or setting the washing temperature to the above-described ranges, the number of times of washing can be significantly reduced.
(dehydration step)
The dehydration step in the method for producing an acrylic rubber bag of the present invention is a step of dehydrating the washed aqueous pellet.
The method for dehydrating the aqueous pellet is not particularly limited as long as the method is a method of extruding water from the aqueous pellet, and it can be usually performed using a dehydrator or the like. This is preferable because the amount of ash in the emulsifier and coagulant present in the aqueous pellet, which cannot be removed in the cleaning step, can be reduced, and the water resistance of the acrylic rubber can be significantly improved.
The dehydrator is not particularly limited, and for example, a centrifuge, a squeezer, a screw extruder, or the like can be used, and particularly, the screw extruder is preferable because the water content of the water-containing pellets can be highly reduced. In centrifugal separators and the like, the adhesive acrylic rubber adheres between the wall surface and the slit, and usually only about 45 to 55 wt% of the acrylic rubber is dehydrated. In contrast, a screw extruder is preferable because it has a structure to forcedly extrude water.
The water content of the dehydrated aqueous pellet is not limited, but is usually in the range of 1 to 50% by weight, preferably in the range of 1 to 40% by weight, more preferably in the range of 10 to 40% by weight, and still more preferably in the range of 15 to 35% by weight. The dehydration time can be shortened by setting the water content after dehydration to the above lower limit or more, whereby deterioration of the acrylic rubber can be suppressed, and the ash content can be more sufficiently reduced by setting the water content after dehydration to the above upper limit or less.
(drying step)
The drying step in the method for producing an acrylic rubber bag of the present invention is a step of drying the dehydrated aqueous pellet to less than 1% by weight.
The method for drying the dehydrated aqueous pellets is not particularly limited, and for example, the dehydrated aqueous pellets may be dried by direct drying, and may be preferably performed using a screw type biaxial extrusion dryer. The screw type biaxial extrusion dryer to be used is not particularly limited as long as it is an extrusion dryer having two screws, and in the present invention, particularly roll processability, banbury processability and strength characteristics of an acrylic rubber bag obtained by drying an aqueous pellet under high shear conditions using a screw type biaxial extrusion dryer having two screws can be highly balanced, and thus are preferable.
In the present invention, the acrylic rubber can be obtained by melting, extrusion-drying, and the like of an aqueous pellet in a screw type biaxial extrusion dryer. The drying temperature (set temperature) of the screw type biaxial extrusion dryer may be appropriately selected, but is usually in the range of 100 to 250 ℃, preferably 110 to 200 ℃, more preferably 120 to 180 ℃, and in this case, the acrylic rubber is preferably dried efficiently without scorching or deterioration.
In the present invention, the acrylic rubber is preferably melted and extrusion-dried under reduced pressure in a screw type biaxial extrusion dryer, and the storage stability is highly improved without impairing the roll processability and strength characteristics of the acrylic rubber bag. In order to remove air existing in the acrylic rubber at this stage and to improve the storage stability, the vacuum degree in the screw type biaxial extrusion dryer is preferably selected appropriately, and is usually in the range of 1 to 50kPa, preferably in the range of 2 to 30kPa, more preferably in the range of 3 to 20 kPa.
In the present invention, it is preferable to melt-knead and dry the acrylic rubber with almost water removed by a screw type biaxial extruder dryer, because the banbury processability is highly improved without impairing the roll processability and strength characteristics of the acrylic rubber bag. The water content of the acrylic rubber is usually less than 1% by weight, preferably 0.8% by weight or less, and more preferably 0.6% by weight or less, as long as the water content is appropriately selected in a state of substantially removing water which highly improves the banbury workability. In the present invention, "melt-kneading" or "melt-kneading and drying" means: in a screw type biaxial extrusion dryer, the acrylic rubber is kneaded (mixed) in a molten state or extruded in a molten state and dried at this stage; or extruding and drying the acrylic rubber by kneading the acrylic rubber in a molten (plasticized) state by a screw type biaxial extrusion dryer.
The maximum torque of the screw type biaxial extrusion dryer used in the present invention is not particularly limited, but is usually 20n·m or more, preferably 25n·m or more, more preferably 30n·m or more, particularly preferably 35n·m or more, and most preferably 40n·m or more. Further, the maximum torque of the screw type biaxial extrusion dryer used in the present invention is usually in the range of 25 to 125n·m, preferably in the range of 30 to 100n·m, more preferably in the range of 35 to 75n·m, particularly preferably in the range of 40 to 60n·m, and in this case, the roll processability, banbury processability and strength characteristics of the produced acrylic rubber bag can be highly balanced, and therefore, it is preferable.
The specific energy consumption of the screw type biaxial extrusion dryer used in the present invention is not particularly limited, but is usually 0.1 to 0.25[ kw.h/kg ] or more, preferably 0.13 to 0.23[ kw.h/kg ], more preferably 0.15 to 0.2[ kw.h/kg ], and the roll processability, banbury processability and strength characteristics of the resulting acrylic rubber bag are highly balanced and therefore preferable.
The specific power of the screw type biaxial extrusion dryer used in the present invention is not particularly limited, but is usually 0.2 to 0.6[ A.h/kg ] or more, preferably 0.25 to 0.55[ A.h/kg ], more preferably 0.35 to 0.5[ A.h/kg ], and the roll processability, banbury processability and strength characteristics of the resulting acrylic rubber bag are highly balanced and therefore preferable.
The shear rate of the screw type biaxial extrusion dryer used in the present invention is not particularly limited, but is usually 40 to 150[1/s ] or more, preferably 45 to 125[1/s ], more preferably 50 to 100[1/s ], and the storage stability, roll processability, banbury processability and strength characteristics of the resulting acrylic rubber bag are highly balanced, and therefore preferable.
The shear viscosity of the acrylic rubber in the screw type biaxial extrusion dryer used in the present invention is not particularly limited, but is usually 4000 to 8000[ pa·s ] or less, preferably 4500 to 7500[ pa·s ], and more preferably 5000 to 7000[ pa·s ], and the storage stability, roll processability, banbury processability and strength characteristics of the obtained acrylic rubber bag are highly balanced and therefore preferable.
The cooling rate of the acrylic rubber bag after drying of the acrylic rubber according to the present invention is not particularly limited, but is usually 40 ℃/hr or more, preferably 50 ℃/hr or more, more preferably 100 ℃/hr or more, and particularly preferably 150 ℃/hr or more, and in this case, the acrylic rubber bag is excellent in storage stability, roll processability, banbury processability, strength characteristics, water resistance and compression set resistance, and can be significantly improved in scorch stability, which is preferred.
The rubber coating step of the present invention is a step of coating the dried rubber with a rubber.
The rubber-coating of the dried rubber is carried out by a conventional method, and for example, the dried rubber can be produced by placing it in a packer and compressing it. The pressure at which the compression is carried out may be appropriately selected depending on the purpose of use, and is usually in the range of 0.1 to 15MPa, preferably in the range of 0.5 to 10MPa, and more preferably in the range of 1 to 5 MPa. The compression time is not particularly limited, and is usually in the range of 1 to 60 seconds, preferably in the range of 5 to 30 seconds, more preferably in the range of 10 to 20 seconds.
The present invention is also capable of producing a sheet-like dry rubber and laminating the same to be subjected to rubber coating. The laminated sheet is preferably packaged in a gel, which is easy to manufacture, has few bubbles (high specific gravity), and is excellent in storage stability, processability, and handleability.
(method for producing acrylic rubber bag through sheet-like Dry rubber)
In the present invention, an acrylic rubber bag having excellent storage stability can be produced by extruding a sheet-like dry rubber by a screw type biaxial extruder and laminating the extruded sheet-like dry rubber to form a bag. Specifically, a screw type biaxial extrusion dryer having a dehydration barrel with a dehydration slit, a dryer barrel under reduced pressure, and a die head at the tip end is used, the above-mentioned washed aqueous pellets are dehydrated to a water content of 1 to 40% by weight by the dehydration barrel, then dried to a water content of less than 1% by weight by the dryer barrel, the sheet-like dried rubber is extruded from the die head, and then the extruded sheet-like dried rubber is cut and laminated, whereby an acrylic rubber bag having a large specific gravity and excellent storage stability can be easily produced.
In the present invention, the aqueous pellets supplied to the screw type biaxial extrusion dryer are preferably pellets from which free water (water removal) is removed after washing.
(Water removal Process)
In the present invention, in order to improve the dewatering efficiency, it is preferable to provide a dewatering step of separating free water from the washed aqueous pellets by a dewatering machine.
As the dewatering machine, a known dewatering machine can be used without particular limitation, and examples thereof include a wire mesh, a screen, an electric screen, and the like, and a wire mesh and a screen are preferable.
The mesh of the dewatering machine is not particularly limited, but is usually in the range of 0.01 to 5mm, preferably in the range of 0.1 to 1mm, more preferably in the range of 0.2 to 0.6mm, and in this case, the loss of the water-containing aggregates is small and the dewatering can be efficiently performed, so that it is preferable.
The water content of the dehydrated aqueous pellet, that is, the water content of the aqueous pellet fed to the dehydration and drying step is not particularly limited, but is usually in the range of 50 to 80% by weight, preferably in the range of 50 to 70% by weight, more preferably in the range of 50 to 60% by weight.
The temperature of the aqueous pellet after the water removal, that is, the temperature of the aqueous pellet to be fed to the dehydration and drying step is not particularly limited, but is usually 40℃or higher, preferably 40 to 100℃or higher, more preferably 50 to 90℃or lower, particularly preferably 55 to 85℃or lower, most preferably 60 to 80℃or lower, and in this case, the aqueous pellet having a specific heat of up to 1.5 to 2.5 KJ/kg.K, which makes it difficult to raise the temperature, can be dehydrated and dried efficiently by using the screw type biaxial extrusion dryer, which is preferred.
(dehydration of aqueous pellets in the barrel section of the dehydrator)
The dehydration of the aqueous pellets was performed using a dehydration barrel in a screw type biaxial extrusion dryer having a dehydration slit. The mesh size of the dewatering slit may be appropriately selected depending on the conditions of use, and is usually in the range of 0.01 to 5mm, preferably in the range of 0.1 to 1mm, more preferably in the range of 0.2 to 0.6mm, and in this case, the loss of the aqueous pellets is small and the dewatering of the aqueous pellets can be efficiently performed, so that it is preferable.
The number of the dehydration cylinders in the screw type biaxial extrusion dryer is not particularly limited, but is usually plural, preferably 2 to 10, more preferably 3 to 6, and in this case, dehydration of the adhesive acrylic rubber can be efficiently performed, which is preferable.
The removal of water from the hydrous pellets in the dewatering barrel is distinguished by the removal of water in a liquid state (drainage) from the dewatering slit and the removal of water in a vapor state (vapor removal), and in the present invention, the drainage is defined as dewatering and the vapor removal is defined as predrying.
In the dehydration of the hydrous pellets, the water discharged from the dehydration slit may be in either a liquid state (drain) or a vapor state (drain), and in the case of using a screw type biaxial extrusion dryer having a plurality of dehydration barrels, it is preferable to efficiently dehydrate the adhesive acrylic rubber by combining drain and drain. The selection of the water-discharge type dehydrator cylinder or the steam-discharge type dehydrator cylinder of the screw type biaxial extrusion dryer having 3 or more dehydrator cylinders may be appropriately performed according to the purpose of use, and generally the water-discharge type cylinders are increased when the ash content in the produced acrylic rubber bag is reduced, and the steam-discharge type cylinders are increased when the water content is reduced.
The setting temperature of the dehydration barrel may be appropriately selected depending on the monomer composition, ash amount, water content, operating conditions and the like of the acrylic rubber, and is usually in the range of 60 to 150 ℃, preferably in the range of 70 to 140 ℃, more preferably in the range of 80 to 130 ℃. The setting temperature of the dehydration barrel for dehydration in a drained state is usually 60 to 120 ℃, preferably 70 to 110 ℃, more preferably 80 to 100 ℃. The set temperature of the dehydration cylinder for dehydration in the vapor-exhausted state is usually in the range of 100 to 150 ℃, preferably in the range of 105 to 140 ℃, and more preferably in the range of 110 to 130 ℃.
The water content after dehydration of the drainage type dehydration in which water is squeezed out of the hydrous pellets is not particularly limited, but is usually 1 to 40% by weight, preferably 5 to 40% by weight, more preferably 5 to 35% by weight, particularly preferably 10 to 35% by weight, and in this case, productivity and ash removal efficiency are highly balanced, and thus preferable.
In the present invention, the water content can be reduced to the above range by using a screw type biaxial extrusion dryer having a dehydration slit and forcibly extruding with a screw, because the acrylic rubber having the adhesiveness of the reactive group adheres to the dehydration slit portion and is hardly dehydrated (the water content is about 45 to 55% by weight) when the dehydration is performed by using a centrifuge or the like.
In the case of dehydration of the aqueous pellets having a water-draining type dehydrator cylinder and a steam-draining type dehydrator cylinder, the water content after water draining in the water-draining type dehydrator cylinder is usually 5 to 40 wt%, preferably 10 to 40 wt%, more preferably 15 to 35 wt%, and the water content after pre-drying in the steam-draining type dehydrator cylinder is usually 1 to 30 wt%, preferably 3 to 20 wt%, more preferably 5 to 15 wt%.
The dehydration time can be shortened and deterioration of the acrylic rubber can be suppressed by setting the water content after dehydration to the above lower limit or more, and the ash content can be more sufficiently reduced by setting the water content after dehydration to the above upper limit or less.
(drying of aqueous pellets in the dryer section)
The above-described drying of the dehydrated aqueous pellets is desirably carried out by a screw type biaxial extrusion dryer having a dryer barrel section under reduced pressure. The drying under reduced pressure is preferable because the drying production efficiency is improved, and the acrylic rubber bag having a high specific gravity and excellent storage stability can be produced by removing air existing inside the acrylic rubber. In the present invention, the acrylic rubber is melted and extrusion-dried under reduced pressure, whereby the storage stability can be highly improved. The storage stability of the acrylic rubber bag is related to the specific gravity of the acrylic rubber bag, and can be controlled, and in the case of being controlled to have a high specific gravity and a high storage stability, the storage stability can be controlled by the degree of vacuum or the like of extrusion drying.
The vacuum degree of the dryer cylinder may be appropriately selected, and is usually 1 to 50kPa, preferably 2 to 30kPa, more preferably 3 to 20kPa, and in this case, it is preferable to be able to dry the aqueous pellets efficiently and to remove air from the acrylic rubber, and to be able to significantly improve the storage stability of the acrylic rubber bag.
The setting temperature of the dryer cylinder may be appropriately selected, and is usually in the range of 100 to 250 ℃, preferably in the range of 110 to 200 ℃, more preferably in the range of 120 to 180 ℃, and in this case, it is preferable to reduce the amount of methyl ethyl ketone insoluble components in the acrylic rubber bag while drying the acrylic rubber efficiently without scorching or deterioration.
The number of the dryer cylinders in the screw type biaxial extrusion dryer is not particularly limited, but is usually plural, preferably 2 to 10, more preferably 3 to 8. The vacuum level in the case of having a plurality of dryer cylinders may be changed by making the entire dryer cylinders approximate to the vacuum level. The set temperature in the case of having a plurality of dryer cylinders may be set to a temperature similar to that of all the dryer cylinders or may be changed, and it is preferable to increase the drying efficiency by increasing the temperature of the discharge portion (side closer to the die) as compared with the temperature of the introduction portion (side closer to the dryer cylinder).
The moisture content of the dried rubber after drying is usually less than 1% by weight, preferably 0.8% by weight or less, more preferably 0.6% by weight or less. In the present invention, it is preferable to melt-extrude the dried rubber in a screw type biaxial extrusion dryer so that the water content of the dried rubber is at this value (the state where water is almost removed), because the amount of methyl ethyl ketone insoluble components in the acrylic rubber can be reduced. In the present invention, the acrylic rubber bag is preferably melt-kneaded or melt-kneaded and dried by a screw type biaxial extruder, because the two properties of strength and Banbury processability are highly balanced. In the present invention, "melt-kneading" or "melt-kneading and drying" means: in a screw type biaxial extrusion dryer, the acrylic rubber is kneaded (mixed) in a molten state or extruded in a molten state and dried at this stage; or extruding and drying the acrylic rubber by kneading the acrylic rubber in a molten (plasticized) state by a screw type biaxial extrusion dryer.
In the present invention, the shear rate of the acrylic rubber in a substantially water-free state in the dryer barrel of the screw type biaxial extrusion dryer is not particularly limited, but is usually 10[1/s ] or more, preferably 10 to 400[1/s ], more preferably 50 to 250[1/s ], and the storage stability, roll processability, banbury processability, strength characteristics and compression set resistance of the obtained acrylic rubber bag are highly balanced and therefore preferable.
In the screw type biaxial extrusion dryer used in the present invention, the shear viscosity of the acrylic rubber in the dryer barrel is not particularly limited, but is usually not more than 12000[ Pa.s ], preferably in the range of 1000 to 12000[ Pa.s ], more preferably in the range of 2000 to 10000[ Pa.s ], particularly preferably in the range of 3000 to 7000[ Pa.s ], most preferably in the range of 4000 to 6000[ Pa.s ], and the storage stability, roll processability, banbury processability and strength characteristics of the obtained acrylic rubber bag are highly balanced, and therefore preferred.
(extrusion of dried rubber from die head)
The dried rubber dehydrated and dried by the screw sections of the dehydration cylinder and the drying cylinder is transported to a die section without rectification of the screw, and extruded into a desired shape from the die section. Between the screw section and the die section, a perforated plate, a metal mesh, or the like may be provided, or may not be provided.
The extruded dry rubber is preferably extruded into a sheet shape by forming the die shape into a substantially rectangular shape, because it is less involved in air, has a large specific gravity, and is excellent in storage stability.
The resin pressure of the die head is not particularly limited, but is usually in the range of 0.1 to 10MPa, preferably in the range of 0.5 to 5MPa, more preferably in the range of 1 to 3MPa, and in this case, the acrylic rubber bag is preferable because of less air entrainment (high specific gravity) and excellent productivity.
Screw type biaxial extrusion dryer and operating conditions
The screw length (L) of the screw type biaxial extrusion dryer to be used may be appropriately selected depending on the purpose of use, and is usually in the range of 3000 to 15000mm, preferably 4000 to 10000mm, more preferably 4500 to 8000 mm.
The screw diameter (D) of the screw type biaxial extrusion dryer to be used may be appropriately selected depending on the purpose of use, and is usually in the range of 50 to 250mm, preferably in the range of 100 to 200mm, more preferably in the range of 120 to 160 mm.
The ratio (L/D) of the screw length (L) to the screw diameter (D) of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 10 to 100, preferably in the range of 20 to 80, more preferably in the range of 30 to 60, and in this case, the water content can be preferably less than 1% by weight without causing a decrease in the molecular weight or scorching of the dried rubber.
The rotation speed (N) of the screw type biaxial extrusion dryer to be used may be appropriately selected depending on the respective conditions, and is usually 10 to 1000rpm, preferably 50 to 750rpm, more preferably 100 to 500rpm, and most preferably 120 to 300rpm, and in this case, the water content of the acrylic rubber bag and the amount of methyl ethyl ketone insoluble components can be efficiently reduced, which is preferable.
The extrusion amount (Q) of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 100 to 1500 kg/hr, preferably 300 to 1200 kg/hr, more preferably 400 to 1000 kg/hr, and most preferably 500 to 800 kg/hr.
The ratio (Q/N) of the extrusion amount (Q) to the rotation speed (N) of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 2 to 10, preferably in the range of 3 to 8, more preferably in the range of 4 to 6.
The maximum torque of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually 30n·m or more, preferably 35n·m or more, and more preferably 40n·m or more. Further, the maximum torque of the screw type biaxial extrusion dryer used in the present invention is usually in the range of 30 to 100n·m, preferably in the range of 35 to 75n·m, more preferably in the range of 40 to 60n·m, and in this case, the roll processability, banbury processability and strength characteristics of the produced acrylic rubber bag can be highly balanced, and therefore, it is preferable.
The specific energy consumption of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 0.1 to 0.25[ kw.h/kg ] or more, preferably in the range of 0.13 to 0.23[ kw.h/kg ], more preferably in the range of 0.15 to 0.2[ kw.h/kg ], and the roll processability, banbury processability and strength characteristics of the resulting acrylic rubber bag are highly balanced and therefore preferable.
The specific power of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 0.2 to 0.6[ A.multidot.h/kg ] or more, preferably 0.25 to 0.55[ A.multidot.h/kg ], more preferably 0.35 to 0.5[ A.multidot.h/kg ], and the roll processability, banbury processability and strength characteristics of the resulting acrylic rubber bag are highly balanced.
The shear rate of the screw type biaxial extrusion dryer used is not particularly limited, but is usually 40 to 150[1/s ] or more, preferably 45 to 125[1/s ], and more preferably 50 to 100[1/s ], and the storage stability, roll processability, banbury processability and strength characteristics of the resulting acrylic rubber bag are highly balanced and therefore preferable.
The shear viscosity of the acrylic rubber in the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually 4000 to 8000[ Pa.s ] or less, preferably 4500 to 7500[ Pa.s ], and more preferably 5000 to 7000[ Pa.s ], and the storage stability, roll processability, banbury processability and strength characteristics of the obtained acrylic rubber bag are highly balanced, and therefore preferable.
In this way, in the present invention, it is preferable to use an extrusion dryer having a twin screw, because dehydration, drying, and molding under high shear conditions can be performed.
(sheet-like Dry rubber)
The shape of the dried rubber extruded from the screw type biaxial extrusion dryer is preferably a sheet shape, since the specific gravity can be increased without involving air, and the storage stability is highly improved. The sheet-like dry rubber extruded from the screw type biaxial extrusion dryer is generally cooled and cut to be used as a sheet-like acrylic rubber.
The thickness of the sheet-like dry rubber extruded from the screw type biaxial extrusion dryer is not particularly limited, but is usually in the range of 1 to 40mm, preferably in the range of 2 to 35mm, more preferably in the range of 3 to 30mm, most preferably in the range of 5 to 25mm, and in this case, the handling property and productivity are excellent, and therefore, it is preferable. In particular, since the thermal conductivity of the sheet-like dry rubber is as low as 0.15 to 0.35W/mK, when the cooling efficiency is improved to significantly improve the productivity, the thickness of the sheet-like dry rubber is usually in the range of 1 to 30mm, preferably in the range of 2 to 25mm, more preferably in the range of 3 to 15mm, and particularly preferably in the range of 4 to 12 mm.
The width of the sheet-like dry rubber extruded from the screw type biaxial extrusion dryer can be appropriately selected depending on the purpose of use, and is usually in the range of 300 to 1200mm, preferably 400 to 1000mm, more preferably 500 to 800 mm.
The temperature of the dried rubber extruded from the screw type biaxial extrusion dryer is not particularly limited, but is usually in the range of 100 to 200 ℃, preferably in the range of 110 to 180 ℃, more preferably in the range of 120 to 160 ℃.
The water content of the dried rubber extruded from the screw type biaxial extrusion dryer is not particularly limited, but is usually less than 1% by weight, preferably 0.8% by weight or less, more preferably 0.6% by weight or less.
The sheet-like dry rubber extruded from the screw type biaxial extrusion dryer is not particularly limited in the complex viscosity ([ eta ]100 ℃) at 100℃and is usually in the range of 1500 to 6000[ Pa.s ], preferably in the range of 2000 to 5000[ Pa.s ], more preferably in the range of 2500 to 4000[ Pa.s ], and most preferably in the range of 2500 to 3500[ Pa.s ], and in this case, the extrudability and shape retention as a sheet are highly balanced and therefore preferred. That is, the extrusion properties can be further improved by the lower limit or more, and the collapse and fracture of the shape of the sheet-like dry rubber can be suppressed by the upper limit or less.
The sheet-like dry rubber extruded from the screw type biaxial extrusion dryer can be folded directly and used, and can be cut off normally.
The sheet-like dry rubber is not particularly limited, and since the acrylic rubber of the present invention has strong adhesiveness, it is preferable to cool the sheet-like dry rubber and then cut the sheet-like dry rubber in order to continuously cut the sheet-like dry rubber without involving air.
The cutting temperature of the sheet-like dry rubber is not particularly limited, but is usually 60℃or lower, preferably 55℃or lower, more preferably 50℃or lower, and in this case, the cutting property and productivity are highly balanced, and therefore, it is preferable.
The sheet-like dry rubber is not particularly limited, and is preferably cut continuously without involving air, because the sheet-like dry rubber has a complex viscosity ([ eta ]60 ℃) of 60℃of usually 15000[ Pa.s ] or less, preferably 2000 to 10000[ Pa.s ], more preferably 2500 to 7000[ Pa.s ], and most preferably 2700 to 5500[ Pa.s ].
The ratio of the complex viscosity at 100 ℃ ([ eta ]100 ℃) to the complex viscosity at 60 ℃ ([ eta ]60 ℃) ([ eta ]100 ℃/[ eta ]60 ℃) is not particularly limited, and it is only required to appropriately select the complex viscosity according to the purpose of use, and it is usually 0.5 or more, preferably 0.6 or more, more preferably 0.7 or more, particularly preferably 0.8 or more, most preferably 0.85 or more, and the upper limit is usually 0.98 or less, preferably 0.97 or less, more preferably 0.96 or less, particularly preferably 0.95 or less, most preferably 0.93 or less, and at this time, the air inclusion property is small, and the cutting and the productivity are highly balanced, so that it is preferable.
The cooling method of the sheet-like dry rubber is not particularly limited, and the sheet-like dry rubber may be left at room temperature, and since the thermal conductivity of the sheet-like dry rubber is extremely small in the range of 0.15 to 0.35W/mK, forced cooling by an air cooling system under ventilation or cold air, a water spraying system, a dipping system in water, or the like is preferable, and an air cooling system under ventilation or cold air is particularly preferable in order to improve productivity.
In the air cooling system of the sheet-like dry rubber, for example, the sheet-like dry rubber can be extruded from a screw extruder onto a conveyor such as a belt conveyor, and conveyed and cooled while blowing cold air. The temperature of the cold air is not particularly limited, and is usually in the range of 0 to 25 ℃, preferably in the range of 5 to 25 ℃, more preferably in the range of 10 to 20 ℃. The length of cooling is not particularly limited, and is usually in the range of 5 to 500m, preferably in the range of 10 to 200m, more preferably in the range of 20 to 100 m.
The cooling rate of the sheet-like dry rubber is not particularly limited, but is usually 40℃per hour or more, preferably 50℃per hour or more, more preferably 100℃per hour or more, particularly preferably 150℃per hour or more, and in this case, it is preferable that the sheet-like dry rubber is easily cut, and the sheet-like dry rubber is not involved in air and has good storage stability. In the present invention, the cooling rate of the sheet-like dry rubber is usually 40℃per hour or more, preferably 50℃per hour or more, more preferably 100℃per hour or more, particularly preferably 150℃per hour or more, and in this case, the scorch stability when the acrylic rubber is coated into a rubber composition is particularly excellent, and therefore, it is preferable.
The cutting length of the sheet-like dry rubber is not particularly limited and may be appropriately selected depending on the purpose of use, and is usually in the range of 100 to 800mm, preferably in the range of 200 to 500mm, more preferably in the range of 250 to 450 mm.
The sheet-like acrylic rubber thus obtained is excellent in handling properties, roll processability, crosslinking properties, strength properties and compression set properties, and also excellent in storage stability, banbury processability and water resistance, as compared with pellet-like acrylic rubber, and can be used as it is, or can be laminated or packaged for use.
(lamination step)
The lamination temperature of the sheet-like dry rubber is not particularly limited, but is usually 30℃or higher, preferably 35℃or higher, more preferably 40℃or higher, and in this case, air involved in lamination can be released, which is preferable. The number of laminated sheets may be appropriately selected according to the size or weight of the acrylic rubber bag. The acrylic rubber bag of the present invention is integrated by the self weight of the laminated sheet-like dry rubber (sheet-like acrylic rubber).
The acrylic rubber bag of the present invention thus obtained is superior to the pellet-like acrylic rubber in handling property, roll processability, crosslinking property, strength property and compression set resistance property, and also superior in storage stability, banbury workability and water resistance, and can be put into a mixer such as a banbury, roll or the like directly or after cutting into a required amount.
< rubber composition >
The rubber composition of the present invention is characterized by comprising a rubber component containing the acrylic rubber bag, a filler and a crosslinking agent.
The acrylic rubber bag of the present invention may be used alone as the rubber component which is the main component of the rubber composition of the present invention, or may be used in combination with other rubber components as required. The content of the acrylic rubber composition of the present invention in the rubber component may be appropriately selected depending on the purpose of use, and is, for example, usually 30% by weight or more, preferably 50% by weight or more, more preferably 70% by weight or more.
The other rubber component to be combined with the acrylic rubber bag of the present invention is not particularly limited, and examples thereof include natural rubber, polybutadiene rubber, polyisoprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, silicone rubber, fluororubber, olefin elastomer, styrene elastomer, vinyl chloride elastomer, polyester elastomer, polyamide elastomer, polyurethane elastomer, polysiloxane elastomer, and the like.
These other rubber components can be used singly or in combination of two or more. The shape of these other rubber components may be any of a pellet, a strand, a bale, a sheet, a powder, and the like. The content of the other rubber component in the whole rubber component may be appropriately selected within a range not to impair the effect of the present invention, and is, for example, generally 70% by weight or less, preferably 50% by weight or less, more preferably 30% by weight or less.
The filler contained in the rubber composition is not particularly limited, and examples thereof include reinforcing fillers and non-reinforcing fillers, and reinforcing fillers are preferable, and in this case, the rubber composition is excellent in roll processability, banbury processability and crosslinking property in a short period of time, and the crosslinked product is highly excellent in water resistance, strength characteristics and compression set resistance, and therefore is preferable.
Examples of the reinforcing filler include: carbon blacks such as furnace black, acetylene black, pyrolytic carbon black, channel black, and graphite; and silica such as wet silica, dry silica and colloidal silica. Examples of the non-reinforcing filler include quartz powder, diatomaceous earth, zinc oxide, basic magnesium carbonate, activated calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, talc, aluminum sulfate, calcium sulfate, and barium sulfate.
These fillers may be used singly or in combination, and the amount thereof may be appropriately selected within a range not to impair the effects of the present invention, and is usually in a range of 1 to 200 parts by weight, preferably in a range of 10 to 150 parts by weight, more preferably in a range of 20 to 100 parts by weight, relative to 100 parts by weight of the rubber component.
The crosslinking agent used in the rubber composition is not particularly limited, and conventionally known crosslinking agents may be selected according to the purpose of use, and examples thereof include inorganic crosslinking agents such as sulfur compounds, organic crosslinking agents, and the like, and organic crosslinking agents are preferable. As the crosslinking agent, either a polyvalent compound or a monovalent compound may be used, and a polyvalent compound having 2 or more reactive groups is preferable. Further, as the crosslinking agent, either an ion-crosslinkable compound or a radical-crosslinkable compound can be used, and an ion-crosslinkable compound is preferable.
The organic crosslinking agent is not particularly limited, but is preferably an ion-crosslinkable organic compound, and particularly preferably a polyion organic compound. When the crosslinking agent is a polyion organic compound (polyion crosslinkable compound), the rubber composition is particularly preferable because it is excellent in roll processability, banbury processability and crosslinking property in a short period of time, and the crosslinked product is highly excellent in water resistance, strength characteristics and compression set resistance. The "ion" of the ion-crosslinkable or multi-element ion is an ion-reactive ion, and is not particularly limited as long as it is an ion-reactive group of the ion-reactive group-containing monomer of the above-mentioned acrylic rubber, and examples thereof include ion-crosslinkable organic compounds having an ion-reactive group such as an amine group, an epoxy group, a carboxyl group, and a thiol group.
Specific examples of the polyionic organic compound include a polyamine compound, a polyepoxide compound, a polycarboxylic acid compound, and a polythiol compound, and the polyamine compound and the polythiol compound are preferable, and the polyamine compound is more preferable.
Examples of the polyamine compound include: aliphatic polyamine compounds such as hexamethylenediamine, hexamethylenediamine carbamate, N' -biscinnamaldehyde-1, 6-hexamethylenediamine; 4,4 '-methylenedianiline, p-phenylenediamine, m-phenylenediamine, 4' -diaminodiphenyl ether, 3,4 '-diaminodiphenyl ether, 4' - (m-phenylenediisopropylene) diphenylamine, 4'- (p-phenylenediisopropylene) diphenylamine aromatic polyamine compounds such as 2,2' -bis [4- (4-aminophenoxy) phenyl ] propane, 4 '-diaminobenzanilide, 4' -bis (4-aminophenoxy) biphenyl, m-xylylenediamine, p-xylylenediamine, and 1,3, 5-benzenetriamine. Among these, hexamethylenediamine carbamate, 2' -bis [4- (4-aminophenoxy) phenyl ] propane, and the like are preferable. Further, as the polyamine compound, carbonates thereof can be preferably used. These polyamine compounds are particularly preferably used in combination with a carboxyl group-containing acrylic rubber bag or an epoxy group-containing acrylic rubber bag.
As the polythiol compounds, preferably using triazine thiol compounds, can be cited for example, 6-three mercapto-s three triazine, 2-two amino-4, 6-two thiol-s three triazine, 1-two butyl amino 3, 5-two mercapto three triazine, 2-two butyl amino 4, 6-two thiol-s three triazine, 1-phenyl amino 3, 5-two mercapto three triazine, 2,4, 6-three mercapto-1, 3,5 three triazine, 1-hexyl amino 3, 5-two mercapto three triazine. These triazine thiol compounds are particularly preferably used in combination with an acrylic rubber bag containing chlorine atoms.
Examples of the other polyvalent organic compound include a polyvalent carboxylic acid compound such as tetradecanedioic acid, and a metal dithiocarbamate such as zinc dimethyldithiocarbamate. These other polyvalent organic compounds are particularly preferably used in combination with an epoxy group-containing acrylic rubber bag.
These crosslinking agents may be used singly or in combination, and the amount thereof is usually 0.001 to 20 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, relative to 100 parts by weight of the rubber component. When the amount of the crosslinking agent is in this range, the rubber elasticity can be made sufficient, and the mechanical strength as a crosslinked rubber product can be made excellent, which is preferable.
The rubber composition of the present invention may contain an antioxidant as needed. The type of the antioxidant is not particularly limited, and examples thereof include: other phenol-based antioxidants such as 2, 6-di-tert-butyl-4-methylphenol, 2, 6-di-tert-butylphenol, butylhydroxyanisole, 2, 6-di-tert-butyl- α -dimethylamino-p-cresol, octadecyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, styrenated phenol, 2' -methylene-bis (6- α -methyl-benzyl-p-cresol), 4' -methylenebis (2, 6-di-tert-butylphenol), 2' -methylene-bis (4-methyl-6-tert-butylphenol), 2, 4-bis [ (octylthio) methyl ] -6-methylphenol, 2' -thiobis- (4-methyl-6-tert-butylphenol), 4' -thiobis- (6-tert-butylphenol), 2, 6-di-tert-butyl-4- [4, 6-bis (octylthio) -1,3, 5-triazin-2-ylamino ] phenol; phosphite antioxidants such as tris (nonylphenyl) phosphite, diphenylisodecyl phosphite, tetraphenyl dipropylene glycol and bisphosphite; thioester-based antioxidants such as dilauryl thiodipropionate; amine-based antioxidants such as phenyl- α -naphthylamine, phenyl- β -naphthylamine, p- (p-toluenesulfonamide) -diphenylamine, 4'- (α, α -dimethylbenzyl) diphenylamine, N-diphenyl-p-phenylenediamine, N-isopropyl-N' -phenyl-p-phenylenediamine, butyraldehyde-aniline condensate, and the like; imidazole-based antioxidants such as 2-mercaptobenzimidazole; quinoline antioxidants such as 6-ethoxy-2, 4-trimethyl-1, 2-dihydroquinoline; hydroquinone-based antioxidants such as 2, 5-di-t-amyl hydroquinone. Among these, amine-based antioxidants are particularly preferable.
These antioxidants may be used alone or in combination of two or more, and the amount thereof is usually in the range of 0.01 to 15 parts by weight, preferably in the range of 0.1 to 10 parts by weight, more preferably in the range of 1 to 5 parts by weight, relative to 100 parts by weight of the rubber component.
The rubber composition of the present invention contains the rubber component containing the acrylic rubber bag of the present invention, a filler and a crosslinking agent as essential components, and optionally contains an anti-aging agent, and optionally contains other additives commonly used in the art, for example, a crosslinking aid, a crosslinking accelerator, a crosslinking retarder, a silane coupling agent, a plasticizer, a processing aid, a lubricant, a pigment, a colorant, an antistatic agent, a foaming agent, and the like, as required. These other compounding agents may be used alone or in combination of two or more kinds, and the compounding amounts thereof may be appropriately selected within a range that does not impair the effects of the present invention.
The method for producing the rubber composition of the present invention includes a method of mixing the rubber component containing the acrylic rubber bag of the present invention, the filler, the crosslinking agent, and optionally the antioxidant and other compounding agents, and any method used in the conventional rubber processing field can be used at the time of mixing, for example, an open roll mill, a Banbury mixer, various kneaders, and the like. The mixing procedure of the components may be performed in a usual order in the field of rubber processing, and it is preferable that, for example, components which are not easily reacted or decomposed by heating are sufficiently mixed and then a crosslinking agent or the like which is a component which is easily reacted or decomposed by heating is mixed for a short period of time at a temperature at which no reaction or decomposition occurs.
< crosslinked rubber >
The rubber crosslinked product of the present invention is obtained by crosslinking the rubber composition.
The rubber crosslinked product of the present invention can be produced by the following method: the rubber composition of the present invention is produced by molding the rubber composition by a molding machine such as an extruder, an injection molding machine, a compressor, or a roll, which corresponds to a desired shape, and curing the shape as a rubber crosslinked product by a crosslinking reaction by heating. In this case, the crosslinking may be performed after the preliminary molding, or may be performed at the same time as the molding. The molding temperature is usually 10 to 200℃and preferably 25 to 150 ℃. The crosslinking temperature is usually 100 to 250 ℃, preferably 130 to 220 ℃, more preferably 150 to 200 ℃, and the crosslinking time is usually 0.1 minutes to 10 hours, preferably 1 minute to 5 hours. As the heating method, a method for crosslinking the rubber such as pressing heating, steam heating, oven heating, and hot air heating may be appropriately selected.
The rubber crosslinked product of the present invention may be subjected to secondary crosslinking by further heating according to the shape, size, etc. of the rubber crosslinked product. The secondary crosslinking varies depending on the heating method, crosslinking temperature, shape, etc., and is preferably carried out for 1 to 48 hours. The heating method and the heating temperature are properly selected.
The rubber crosslinked product of the present invention maintains tensile strength, elongation, hardness, etc. as basic properties of rubber, and has excellent compression set resistance and water resistance.
The rubber crosslinked material of the present invention can be preferably used as, for example, by effectively utilizing the above characteristics: sealing materials such as O-rings, sealing materials, diaphragms, oil seals, shaft seals, bearing seals, mechanical seals, wellhead seals, seals for electrical/electronic devices, and seals for air compression devices; various gaskets such as a rocker cover gasket attached to a connecting portion between a cylinder block and a cylinder head, an oil pan gasket attached to a connecting portion between an oil pan and a cylinder head or a transmission case, a gasket for a fuel cell spacer attached between a pair of cases sandwiching a battery cell having a positive electrode, an electrolyte plate, and a negative electrode, and a gasket for a top cover of a hard disk drive; a buffer material and a vibration-proof material; a wire coating material; industrial belts; tubes/hoses; sheets, and the like.
The rubber crosslinked product of the present invention is preferably used as an extrusion molded product and a die crosslinked product for automotive applications, for example, in various hoses such as fuel oil hoses such as fuel tanks, fuel neck hoses, exhaust hoses, paper hoses, oil hoses, air hoses such as turbo air hoses and mission control hoses, radiator hoses, heater hoses, brake hoses, and air conditioning hoses.
< Structure of apparatus for manufacturing acrylic rubber bag >
Next, a structure of an apparatus for manufacturing an acrylic rubber bag according to an embodiment of the present invention will be described. Fig. 1 is a diagram schematically showing an example of an acrylic rubber manufacturing system having an apparatus structure for manufacturing an acrylic rubber bag according to an embodiment of the present invention. In the production of the acrylic rubber of the present invention, for example, the acrylic rubber production system 1 shown in fig. 1 can be used.
The acrylic rubber production system 1 shown in fig. 1 is composed of an emulsion polymerization reactor, a coagulation device 3, a cleaning device 4, a water remover 43, and a screw type biaxial extrusion dryer, which are not shown.
The emulsion polymerization reactor is configured to perform the treatment in the emulsion polymerization step. Although not shown in fig. 1, the emulsion polymerization reactor includes, for example, a polymerization reaction tank, a temperature control unit for controlling a reaction temperature, and a stirring device having a motor and stirring blades. In the emulsion polymerization reactor, water and an emulsifier are mixed with a monomer component for forming an acrylic rubber, and the mixture is emulsified while being properly stirred by a stirrer, and an emulsion polymerization reaction is initiated in the presence of a redox catalyst comprising an inorganic radical generator and a reducing agent, and a chain transfer agent is added after the batch during the polymerization, whereby an emulsion polymerization liquid can be obtained. The emulsion polymerization reactor may be any of a batch type, a semi-batch type and a continuous type, or may be any of a tank type reactor and a tube type reactor.
The coagulation apparatus 3 shown in fig. 1 is configured to perform the treatment in the coagulation step. As schematically illustrated in fig. 1, the solidification apparatus 3 includes, for example, a stirring tank 30, a heating unit 31 for heating the inside of the stirring tank 30, a temperature control unit not shown for controlling the temperature in the stirring tank 30, a stirring device 34 including a motor 32 and stirring blades 33, and a drive control unit not shown for controlling the rotational speed and rotational speed of the stirring blades 33. In the coagulation apparatus 3, the aqueous pellets can be produced by bringing the emulsion polymerization liquid obtained in the emulsion polymerization reactor into contact with a coagulation liquid to coagulate the emulsion polymerization liquid.
For example, the coagulation device 3 may be configured to contact the emulsion polymerization liquid with the coagulation liquid by adding the emulsion polymerization liquid to the stirred coagulation liquid. That is, the agitation tank 30 of the coagulation device 3 is filled with a coagulation liquid in advance, and an emulsion polymerization liquid is added to the coagulation liquid and brought into contact therewith to coagulate the emulsion polymerization liquid, thereby producing an aqueous pellet.
The heating unit 31 of the solidifying apparatus 3 is configured to heat the solidifying liquid filled in the stirring tank 30. The temperature control unit of the solidification apparatus 3 is configured to control the temperature in the stirring tank 30 by controlling the heating operation of the heating unit 31 while monitoring the temperature in the stirring tank 30 measured by the thermometer. The temperature of the solidification liquid in the stirring tank 30 is controlled to be normally 40 ℃ or higher, preferably 40 to 90 ℃, and more preferably 50 to 80 ℃ by the temperature control unit.
The stirring device 34 of the solidifying apparatus 3 is configured to stir the solidification liquid filled in the stirring tank 30. Specifically, the stirring device 34 includes a motor 32 that generates rotational power and stirring blades 33 that are deployed in a direction perpendicular to a rotation axis of the motor 32. The stirring blade 33 can rotate around a rotation axis by the rotation power of the motor 32 in the coagulation liquid filled in the stirring tank 30, thereby allowing the coagulation liquid to flow. The shape, size, number of the stirring blades 33, and the like are not particularly limited.
The drive control unit of the coagulation device 3 is configured to control the rotational drive of the motor 32 of the stirring device 34, and to set the rotational speed and the rotational speed of the stirring blade 33 of the stirring device 34 to predetermined values. The rotation of the stirring blade 33 is controlled by the drive control unit so that the stirring number of the coagulation liquid is, for example, usually 100rpm or more, preferably in the range of 200 to 1000rpm, more preferably in the range of 300 to 900rpm, and particularly preferably in the range of 400 to 800 rpm. The rotation of the stirring blade 33 is controlled by the drive control unit so that the peripheral speed of the solidification liquid is usually 0.5m/s or more, preferably 1m/s or more, more preferably 1.5m/s or more, particularly preferably 2m/s or more, and most preferably 2.5m/s or more. Further, the rotation of the stirring blade 33 is controlled by the drive control unit so that the upper limit value of the peripheral speed of the solidification liquid is usually 50m/s or less, preferably 30m/s or less, more preferably 25m/s or less, and most preferably 20m/s or less.
The cleaning apparatus 4 shown in fig. 1 is configured to perform the processing in the above-described cleaning process. As schematically illustrated in fig. 1, the cleaning apparatus 4 includes, for example, a cleaning tank 40, a heating unit 41 for heating the interior of the cleaning tank 40, and a temperature control unit, not illustrated, for controlling the temperature in the cleaning tank 40. In the cleaning device 4, the aqueous pellets produced in the coagulation device 3 are mixed with a large amount of water and cleaned, whereby the ash content in the finally obtained acrylic rubber bag can be effectively reduced.
The heating unit 41 of the cleaning device 4 is configured to heat the inside of the cleaning tank 40. The temperature control unit of the cleaning apparatus 4 is configured to control the temperature in the cleaning tank 40 by controlling the heating operation of the heating unit 41 while monitoring the temperature in the cleaning tank 40 measured by the thermometer. As described above, the temperature of the washing water in the washing tub 40 is controlled to be normally 40 ℃ or higher, preferably 40 to 100 ℃, more preferably 50 to 90 ℃, and most preferably 60 to 80 ℃.
The aqueous pellets washed by the washing apparatus 4 are supplied to a screw type biaxial extrusion dryer 5 which performs a dehydration step and a drying step. At this time, the washed aqueous pellets are preferably supplied to the screw type biaxial extrusion dryer 5 through a water remover 43 capable of separating free water. The water remover 43 can use, for example, a metal mesh, a screen, an electric screen, or the like.
When the washed aqueous pellets are fed to the screw type biaxial extruder dryer 5, the temperature of the aqueous pellets is preferably 40 ℃ or higher, more preferably 60 ℃ or higher. For example, the temperature of the water used for washing in the washing device 4 may be set to 60 ℃ or higher (for example, 70 ℃) so that the temperature of the aqueous pellets at the time of being supplied to the screw type biaxial extrusion dryer 5 can be maintained to 60 ℃ or higher, or may be heated so that the temperature of the aqueous pellets is 40 ℃ or higher, preferably 60 ℃ or higher at the time of being transported from the washing device 4 to the screw type biaxial extrusion dryer 5. This can effectively perform the dehydration step and the drying step as subsequent steps, and can greatly reduce the water content of the finally obtained dried rubber.
The screw type biaxial extrusion dryer 5 shown in fig. 1 is configured to perform the above-described dehydration step and the drying step. In addition, although a screw type biaxial extrusion dryer 5 is shown as a preferable example in fig. 1, a centrifugal separator, a squeezer, or the like may be used as a dehydrator for performing the processing in the dehydration step, and a hot air dryer, a reduced pressure dryer, an expansion dryer, a kneading type dryer, or the like may be used as a dryer for performing the processing in the drying step.
The screw type biaxial extrusion dryer 5 is configured to mold the dried rubber obtained through the dehydration step and the drying step into a predetermined shape and discharge the molded rubber. Specifically, the screw type biaxial extrusion dryer 5 is configured to have a dehydrator cylinder 53 and a dryer cylinder 54, and a die 59 is further provided on the downstream side of the screw type biaxial extrusion dryer 5, wherein the dehydrator cylinder 53 has a function as a dehydrator for dehydrating the aqueous pellets washed by the washing device 4, the dryer cylinder 54 has a function as a dryer for drying the aqueous pellets, and the die 59 has a molding function for molding the aqueous pellets.
The structure of the screw type biaxial extrusion dryer 5 will be described below with reference to fig. 2. Fig. 2 shows a structure of a preferable specific example of the screw type biaxial extrusion dryer 5 shown in fig. 1. The above-described dehydration/drying step can be suitably performed by the screw type biaxial extrusion dryer 5.
The screw type biaxial extrusion dryer 5 shown in fig. 2 is a biaxial screw type extrusion dryer having a pair of screws not shown in the figure in a barrel unit 51. The screw type biaxial extrusion dryer 5 has a drive unit 50 that rotationally drives a pair of screws in a barrel unit 51. The acrylic rubber can be dried by applying high shear to the acrylic rubber by this structure, and is preferable. The drive unit 50 is mounted at the upstream end (left end in fig. 2) of the barrel unit 51. Further, the screw type biaxial extrusion dryer 5 has a die 59 at the downstream end (right end in fig. 2) of the barrel unit 51.
From the upstream side to the downstream side (from the left side to the right side in fig. 2), the barrel unit 51 has a supply barrel portion 52, a dehydration barrel portion 53, and a dryer barrel portion 54.
The supply cylinder portion 52 is composed of 2 supply cylinders, i.e., a 1 st supply cylinder 52a and a 2 nd supply cylinder 52 b.
The dewatering cylinder section 53 is composed of 3 dewatering cylinders, namely, a 1 st dewatering cylinder 53a, a 2 nd dewatering cylinder 53b, and a 3 rd dewatering cylinder 53 c.
The dryer section 54 is composed of 8 dryer cylinders, i.e., a 1 st dryer cylinder 54a, a 2 nd dryer cylinder 54b, a 3 rd dryer cylinder 54c, a 4 th dryer cylinder 54d, a 5 th dryer cylinder 54e, a 6 th dryer cylinder 54f, a 7 th dryer cylinder 54g, and an 8 th dryer cylinder 54 h.
The barrel unit 51 is constituted by connecting 13 divided barrels 52a to 52b, 53a to 53c, 54a to 54h from the upstream side to the downstream side.
The screw type biaxial extrusion dryer 5 further includes heating means, not shown, for heating the respective cylinders 52a to 52b, 53a to 53c, 54a to 54h, and heating the aqueous pellets in the respective cylinders 52a to 52b, 53a to 53c, 54a to 54h to a predetermined temperature. The heating units have numbers corresponding to the respective barrels 52a to 52b, 53a to 53c, 54a to 54 h. As such heating means, for example, a structure in which high-temperature steam or the like is supplied from a steam supply means to a steam flow jacket formed in each of the cylinders 52a to 52b, 53a to 53c, 54a to 54h can be used, but the invention is not limited thereto. The screw type biaxial extrusion dryer 5 further includes a temperature control unit, not shown, for controlling the set temperatures of the heating units corresponding to the respective cylinders 52a to 52b, 53a to 53c, and 54a to 54 h.
The number of supply cylinders, dewatering cylinders, and drying cylinders constituting the respective cylinder sections 52, 53, and 54 in the cylinder unit 51 is not limited to the one shown in fig. 2, and may be set to a number corresponding to the water content of the aqueous pellets of the acrylic rubber to be dried.
For example, the number of supply barrels to the barrel portion 52 may be, for example, 1 to 3. In addition, when the number of the dehydrator cylinders of the dehydrator cylinder part 53 is, for example, 2 to 10, preferably 3 to 6, dehydration of the water-containing pellets of the adhesive acrylic rubber can be performed efficiently, which is more preferable. The number of the dryer cylinders of the dryer cylinder section 54 is preferably 2 to 10, more preferably 3 to 8, for example.
The pair of screws in the barrel unit 51 are rotationally driven by a driving unit such as a motor accommodated in the driving unit 50. The pair of screws extend from the upstream side to the downstream side in the barrel unit 51, and by the rotation driving, the aqueous pellets supplied to the supply barrel unit 52 can be conveyed to the downstream side while being mixed. The pair of screws are preferably biaxial meshing type in which the screw ridge portions and the screw groove portions are meshed with each other, whereby the dewatering efficiency and drying efficiency of the aqueous pellet can be improved.
The rotation direction of the pair of screws may be the same direction or different directions, and from the viewpoint of self-cleaning performance, the pair of screws are preferably rotated in the same direction. The screw shape of the pair of screws is not particularly limited as long as it is a shape required in each of the cylinder portions 52, 53, 54.
The supply cylinder section 52 is a region in which the aqueous pellets are supplied into the cylinder unit 51. The 1 st supply cylinder 52a of the supply cylinder section 52 has a feed port 55 for supplying the aqueous pellets into the cylinder unit 51.
The dewatering cylinder 53 is a region in which a liquid (slurry) containing a coagulant or the like is separated from the aqueous pellet and discharged.
The 1 st to 3 rd dewatering cylinders 53a to 53c constituting the dewatering cylinder 53 have dewatering slits 56a, 56b, 56c for discharging the water of the aqueous pellets to the outside, respectively. A plurality of dewatering slits 56a, 56b, 56c are formed in each dewatering cylinder 53a to 53 c.
The slit width, that is, the mesh width of each dewatering slit 56a, 56b, 56c may be appropriately selected depending on the conditions of use, and is usually 0.01 to 5mm, preferably 0.1 to 1mm, more preferably 0.2 to 0.6mm, from the viewpoint that the loss of the aqueous pellets is small and the dewatering of the aqueous pellets can be efficiently performed.
The removal of water from the hydrous pellets in each of the dewatering cylinders 53a to 53c of the dewatering cylinder 53 is performed in both a liquid state and a vapor state from each of the dewatering slits 56a, 56b, 56 c. In the dehydrator cylinder 53 of the present embodiment, the case of removing water in a liquid state is defined as drain, and the case of removing water in a vapor state is defined as drain.
The combination of water discharge and steam discharge in the dehydrator cylinder 53 is preferable because the water content of the adhesive acrylic rubber can be reduced efficiently. In the dewatering cylinder section 53, which of the 1 st to 3 rd dewatering cylinders 53a to 53c is used for dewatering or discharging steam is appropriately set according to the purpose of use, and in general, in the case of reducing the ash content in the produced acrylic rubber, the dewatering cylinder for dewatering can be increased. In this case, for example, as shown in fig. 2, the 1 st and 2 nd dewatering cylinders 53a and 53b on the upstream side are used for water discharge, and the 3 rd dewatering cylinder 53c on the downstream side is used for steam discharge. For example, in the case where the dewatering cylinder portion 53 has 4 dewatering cylinders, it is conceivable to drain water from the 3 dewatering cylinders on the upstream side and drain steam from the 1 dewatering cylinder on the downstream side. On the other hand, in the case of decreasing the water content, a dehydration cylinder in which steam discharge is performed may be increased.
As described above in the dehydration and drying step, the set temperature of the dehydration barrel section 53 is usually in the range of 60 to 150 ℃, preferably in the range of 70 to 140 ℃, more preferably in the range of 80 to 130 ℃, the set temperature of the dehydration barrel for dehydration in a water discharge state is usually 60 to 120 ℃, preferably 70 to 110 ℃, more preferably 80 to 100 ℃, and the set temperature of the dehydration barrel for dehydration in a steam discharge state is usually in the range of 100 to 150 ℃, preferably 105 to 140 ℃, more preferably 110 to 130 ℃.
The dryer cylinder 54 is a region in which the dehydrated aqueous pellets are dried under reduced pressure. The 2 nd, 4 th, 6 th, and 8 th dryer barrels 54b, 54d, 54f, and 54h constituting the dryer barrel section 54 have exhaust ports 58a, 58b, 58c, 58d for degassing, respectively. The exhaust ports 58a, 58b, 58c, and 58d are connected to exhaust pipes, not shown.
The ends of the exhaust pipes are connected to vacuum pumps, not shown, respectively, and the interior of the dryer cylinder 54 is depressurized to a predetermined pressure by the operation of these vacuum pumps. The screw extruder 5 has a pressure control unit, not shown, for controlling the operation of these vacuum pumps to control the vacuum degree in the dryer barrel 54.
The vacuum degree in the dryer cylinder 54 may be appropriately selected, and is usually set to 1 to 50kPa, preferably 2 to 30kPa, and more preferably 3 to 20kPa as described above.
The temperature to be set in the dryer barrel 54 may be appropriately selected, and is usually set to 100 to 250 ℃, preferably 110 to 200 ℃, and more preferably 120 to 180 ℃ as described above.
In each of the dryer cylinders 54a to 54h constituting the dryer cylinder section 54, the set temperatures in all of the dryer cylinders 54a to 54h may be similar or different, and it is preferable that the drying efficiency is improved when the temperature on the downstream side (the die 59 side) is set to a higher temperature than the temperature on the upstream side (the dryer cylinder section 53 side).
The die 59 is a die disposed at the downstream end of the barrel unit 51, and has a discharge port having a predetermined nozzle shape. The acrylic rubber dried in the dryer cylinder 54 is extruded into a shape corresponding to a predetermined nozzle shape by passing through the discharge port of the die 59. The acrylic rubber passing through the die 59 can be molded into various shapes such as a pellet, a column, a round bar, a sheet, etc., depending on the nozzle shape of the die 59, and is molded into a sheet in the present invention. Between the screw and the die 59, a perforated plate, a metal mesh, or the like may be provided.
The aqueous pellets of the acrylic rubber obtained through the cleaning step are supplied from the feed port 55 to the supply cylinder portion 52. The aqueous pellets supplied to the supply cylinder section 52 are transported from the supply cylinder section 52 to the dehydration cylinder section 53 by rotation of a pair of screws in the cylinder unit 51. In the dewatering cylinder 53, the dewatering slits 56a, 56b, and 56c provided in the 1 st to 3 rd dewatering cylinders 53a to 53c are used to drain water and steam contained in the aqueous pellets, respectively, and the aqueous pellets are dewatered as described above.
The hydrous pellets dehydrated in the dehydration cylinder section 53 are conveyed to the dryer cylinder section 54 by the rotation of a pair of screws in the cylinder unit 51. The aqueous pellets conveyed to the dryer section 54 are plasticized and mixed into a molten mass, and conveyed downstream while being heated. Then, the moisture contained in the acrylic rubber melt is vaporized, and the moisture (vapor) is discharged to the outside through a not-shown exhaust pipe connected to each of the exhaust ports 58a, 58b, 58c, and 58 d.
As described above, the aqueous pellets are dried by the dryer barrel 54 to obtain a melt of the acrylic rubber, which is supplied to the die 59 by the rotation of the pair of screws in the barrel unit 51, and extruded from the die 59.
Here, an example of the operating conditions of the screw type biaxial extrusion dryer 5 of the present embodiment is given.
The rotation speed (N) of the pair of screws in the barrel unit 51 may be appropriately selected depending on each condition, and is usually 10 to 1000rpm, and from the viewpoint of being able to efficiently reduce the water content of the acrylic rubber and the amount of methyl ethyl ketone insoluble components, it is preferably 50 to 750rpm, more preferably 100 to 500rpm, and most preferably 120 to 300rpm.
The extrusion amount (Q) of the acrylic rubber is not particularly limited, but is usually 100 to 1500 kg/hr, preferably 300 to 1200 kg/hr, more preferably 400 to 1000 kg/hr, and most preferably 500 to 800 kg/hr.
The ratio (Q/N) of the extrusion amount (Q) of the acrylic rubber to the rotational speed (N) of the screw is not particularly limited, but is usually 1 to 20, preferably 2 to 10, more preferably 3 to 8, particularly preferably 4 to 6.
The maximum torque in the barrel unit 51 is not particularly limited, and is usually in the range of 30 to 100n·m, preferably in the range of 35 to 75n·m, and more preferably in the range of 40 to 60n·m.
The specific energy consumption in the cylinder unit 51 is not particularly limited, but is usually 0.1 to 0.25[ kw.h/kg ] or more, preferably in the range of 0.13 to 0.23[ kw.h/kg ], more preferably in the range of 0.15 to 0.2[ kw.h/kg ].
The specific power in the cylinder unit 51 is not particularly limited, but is usually 0.2 to 0.6[ A.multidot.h/kg ] or more, preferably in the range of 0.25 to 0.55[ A.multidot.h/kg ], more preferably in the range of 0.35 to 0.5[ A.multidot.h/kg ].
The shear rate in the barrel unit 51 is not particularly limited, but is usually 40 to 150[ l/s ] or more, preferably 45 to 125[ l/s ], and more preferably 50 to 100[ l/s ].
The shear viscosity of the acrylic rubber in the cylinder unit 51 is not particularly limited, but is usually 4000 to 8000[ Pa.s ] or less, preferably 4500 to 7500[ Pa.s ], and more preferably 5000 to 7000[ Pa.s ].
The cooling device 6 shown in fig. 1 is configured to cool the dried rubber obtained through the dehydration step by a dehydrator and the drying step by a dryer. As the cooling method by the cooling device 6, various methods including an air cooling method under ventilation or cool air, a water spraying method, a dipping method in water, and the like can be employed. In addition, the rubber may also be dried by cooling at room temperature.
As described above, the dried rubber discharged from the screw extruder 5 is extruded into various shapes such as a pellet, a column, a round bar, a sheet, etc., according to the nozzle shape of the die 59, and is molded into a sheet in the present invention. A conveyor type cooling device 60 for cooling the sheet-shaped dried rubber 10 molded into a sheet shape, which is an example of the cooling device 6, will be described below with reference to fig. 3.
Fig. 3 shows a structure of a conveyor type cooling device 60 which is preferable as the cooling device 6 shown in fig. 1. The conveying type cooling device 60 shown in fig. 3 is configured to cool by an air cooling system while conveying the sheet-like dry rubber 10 discharged from the discharge port of the die 59 of the screw extruder 5. By using this conveying type cooling device 60, the sheet-like dry rubber discharged from the screw extruder 5 can be cooled preferably.
The conveying type cooling device 60 shown in fig. 3 is used, for example, by being directly connected to the die 59 of the screw type extruder 5 shown in fig. 2, or being disposed in the vicinity of the die 59.
The conveying type cooling device 60 has a conveyor 61 that conveys the sheet-like dry rubber 10 discharged from the die 59 of the screw extruder 5 in the direction of arrow a in fig. 3, and a cooling unit 65 that blows cool air to the sheet-like dry rubber 10 on the conveyor 61.
The conveyor 61 includes rollers 62 and 63, and a conveyor belt 64 wound around the rollers 62 and 63 and carrying the sheet-like dry rubber 10 thereon. The conveyor 61 is configured to continuously convey the sheet-like dry rubber 10 discharged from the die 59 of the screw extruder 5 to the downstream side (right side in fig. 3) on the conveyor belt 64.
The cooling unit 65 is not particularly limited, and examples thereof include a cooling unit having a structure capable of blowing cooling air sent from a cooling air generating unit, not shown, onto the surface of the sheet-like dry rubber 10 on the conveyor belt 64.
The length L1 of the conveyor 61 and the cooling unit 65 of the conveyor type cooling device 60 (the length of the portion capable of blowing cooling air) is not particularly limited, and is, for example, 10 to 100m, preferably 20 to 50m. The conveying speed of the sheet-like dried rubber 10 in the conveying type cooling device 60 may be appropriately adjusted according to the length L1 of the conveyor 61 and the cooling unit 65, the discharge speed of the sheet-like dried rubber 10 discharged from the die 59 of the screw extruder 5, the target cooling speed, the cooling time, and the like, and is, for example, 10 to 100 m/hr, and more preferably 15 to 70 m/hr.
According to the conveying type cooling device 60 shown in fig. 3, the sheet-like dry rubber 10 discharged from the die 59 of the screw extruder 5 is conveyed by the conveyor 61, and at the same time, cooling air from the cooling unit 65 is blown to the sheet-like dry rubber 10, whereby cooling of the sheet-like dry rubber 10 is performed.
The transport cooling device 60 is not particularly limited to the structure having 1 conveyor 61 and 1 cooling unit 65 as shown in fig. 3, and may have a structure having 2 or more conveyors 61 and 2 or more cooling units 65 corresponding thereto. In this case, the total length of each of the 2 or more conveyors 61 and the cooling unit 65 may be set within the above range.
The glue coating device 7 shown in fig. 1 is constituted as follows: the dried rubber extruded from the screw extruder 5 and cooled by the cooling device 6 is processed to produce a bale as a single piece. As described above, the screw extruder 5 can extrude the dried rubber into various shapes such as a pellet shape, a column shape, a round bar shape, and a sheet shape, and the rubber coating device 7 is configured to carry out rubber coating on the dried rubber molded into various shapes. The weight, shape, etc. of the acrylic rubber bag produced by the rubber bag-coating apparatus 7 are not particularly limited, and for example, a substantially rectangular parallelepiped-shaped acrylic rubber of about 20kg can be produced.
The rubber packing device 7 may have, for example, a packer (baling) by which the cooled dry rubber is compressed to manufacture an acrylic rubber packing.
In addition, in the case of producing the sheet-like dry rubber 10 by the screw extruder 5, a rubber-coated acrylic rubber in which the sheet-like dry rubber 10 is laminated can be produced. For example, a cutter structure for cutting the sheet-like dried rubber 10 may be provided in the rubber packing device 7 disposed downstream of the conveyor-type cooling device 60 shown in fig. 3. Specifically, the cutting structure of the glue wrapping device 7 is configured in the following manner, for example: the cooled sheet-like dried rubber 10 is continuously cut at predetermined intervals, and the cut sheet-like dried rubber 16 is processed into a predetermined size. The cut sheet-like dried rubber 16 cut into a predetermined size by the cutting structure is laminated in a plurality of sheets, whereby an acrylic rubber bag in which the cut sheet-like dried rubber 16 is laminated can be manufactured.
In the case of producing an acrylic rubber bag in which the sliced dried rubber 16 is laminated, it is preferable to laminate the sliced dried rubber 16 at 40 ℃ or higher, for example. By stacking the sliced dried rubber 16 at 40 ℃ or higher, good air discharge can be achieved by further cooling and compression by its own weight.
Examples
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. Unless otherwise specified, "parts", "%" and "ratio" in each example are on a weight basis. The physical properties and the like of the various materials were evaluated by the following methods.
[ monomer composition ]
Regarding the monomer composition in the acrylic rubber, the polymerization is carried out by 1 The monomer structure of each monomer unit in the acrylic rubber was confirmed by H-NMR, and the activity of the reactive group remaining in the acrylic rubber and the content of each reactive group were confirmed by the following method. In addition, each monomer unit is formed in acrylic rubberThe content ratio of the gum was calculated from the amount of each monomer used for polymerization reaction and the polymerization conversion. Specifically, since the polymerization reaction is an emulsion polymerization reaction, the polymerization conversion rate is approximately 100%, and the unreacted monomer cannot be confirmed, the content ratio of each monomer unit is the same as the amount of each monomer used.
[ reactive group content ]
The content of the reactive group in the acrylic rubber bag was measured by the following method.
(1) The carboxyl group amount was calculated by dissolving the rubber sample in acetone and potentiometric titration with potassium hydroxide solution.
(2) The amount of epoxy groups was calculated by dissolving the sample in methyl ethyl ketone, adding an equivalent amount of hydrochloric acid thereto to react with epoxy groups, and titrating the amount of residual hydrochloric acid with potassium hydroxide.
(3) The chlorine amount was calculated by completely burning the sample in a burning flask, absorbing the generated chlorine with water, and titrating with silver nitrate.
[ Ash content ]
The ash content (%) contained in the acrylic rubber bag was measured in accordance with JIS K6228A method.
[ ash component amount ]
The amount (ppm) of each component in the acrylic rubber-coated ash was obtained by pressing ash collected at the time of measuring the ash against titration filter paper having a diameter of 20mm, and measuring XRF using ZSX Primus (manufactured by Kyowa Co., ltd.).
[ molecular weight and molecular weight distribution ]
The weight average molecular weight (Mw) and the molecular weight distribution (Mw/Mn and Mz/Mw) of the acrylic rubber were determined by GPC-MALS method using, as a solvent, a solution in which lithium chloride and 37% concentrated hydrochloric acid were added to dimethylformamide to give a concentration of 0.05mol/L lithium chloride and a concentration of 0.01% hydrochloric acid, respectively, and an absolute molecular weight distribution in which a polymer region is a major part were measured by GPC-MALS method.
The gel permeation chromatography multi-angle light scattering detector used in the present apparatus was composed of a pump (manufactured by LC-20ADOpt corporation, shimadzu corporation) and a differential refractive optical detector (manufactured by Optilab rEX Huai Ya Studies Co., ltd.) as a detector, and a multi-angle light scattering detector (manufactured by DAWN HELEOS Huai Ya Studies Co., ltd.). Specifically, a multi-angle laser light scattering detector (MALS) and a differential refractive index detector (RI) are assembled in a GPC (gel permeation chromatography ) apparatus, and the molecular weight of a solute and its content are calculated in order by measuring the light scattering intensity and refractive index difference of a molecular chain solution classified by size by the GPC apparatus according to the elution time. The measurement conditions and measurement methods using the GPC apparatus are as follows.
Column: TSKgel alpha-M2 root%
Figure BDA0004113404120000601
Manufactured by Tosoh corporation
Column temperature: 40 DEG C
Flow rate: 0.8ml/mm
Sample preparation: to 10mg of the sample (acrylic rubber bag) was added 5ml of the solvent, and the mixture was stirred slowly at room temperature (dissolution was visually confirmed). Then, filtration was performed using a 0.5 μm filter.
[ glass transition temperature (Tg) ]
The glass transition temperature (Tg) of the acrylic rubber was measured by a differential scanning calorimeter (DSC, product name "X-DSC7000", manufactured by Hitachi high technology, co., ltd.).
[ amount of methyl ethyl ketone insoluble component ]
The amount (%) of the insoluble component in methyl ethyl ketone in the acrylic rubber bag was determined by the following method.
About 0.2g (Xg) of an acrylic rubber bag was weighed, immersed in 100ml of methyl ethyl ketone, left at room temperature for 24 hours, and then insoluble components in methyl ethyl ketone were filtered using an 80 mesh metal mesh to obtain a filtrate, namely, a filtrate in which only the methyl ethyl ketone-soluble rubber component was dissolved, and the filtrate was evaporated, dried and solidified, and the obtained dry solid component (Yg) was weighed and calculated by the following formula.
Methyl ethyl ketone insoluble component amount (%) =100× (X-Y)/X
[ specific gravity ]
The specific gravity of the acrylic rubber bag was measured in accordance with JIS K6268 crosslinked rubber-density measurement method A.
The measured value obtained by the following measuring method was the density, and the density of water was 1Mg/m 3 Specific gravity at that time. Specifically, the specific gravity of the rubber sample obtained by the method a according to JIS K6268 cross-linked rubber-density measurement is the specific gravity obtained by dividing the mass by the volume of the voids containing the rubber sample, and the specific gravity obtained by dividing the density of the rubber sample obtained by the method a according to JIS K6268 cross-linked rubber-density measurement by the density of water (when the density of the rubber sample is divided by the density of water, the values are the same, and the unit disappears). Specifically, the specific gravity of the rubber sample was determined based on the following procedure.
(1) 2.5g of a test piece was cut out from a rubber sample left standing at a standard temperature (23 ℃ C.+ -. 2 ℃ C.) for at least 3 hours, and the test piece was hung on a hook on a chemical balance having an accuracy of 1mg using a fine nylon yarn having a mass of less than 0.010g so that the bottom edge of the test piece was 25mm above a distribution plate for the chemical balance, and the mass (m 1) to mg of the test piece was measured 2 times in the atmosphere.
(2) Next, 250cm of the solution was placed on a distribution plate for a chemical balance 3 The beaker was filled with distilled water which was boiled and cooled to a standard temperature, the test piece was immersed therein, bubbles adhering to the surface of the test piece were removed, the movement of the pointer of the balance was observed for several seconds, it was confirmed that the pointer was not slowly swung by convection, and the mass (m 2) of the test piece in water was measured in mg units 2 times.
(3) In addition, when the density of the test piece is less than 1Mg/m 3 When (when the test piece was floating in water), a weight was added to the test piece, and the weight of the weight in water (m 3), the weight of the test piece, and the weight of the weight (m 4) were measured 2 times in mg units.
(4) Using the average value of each of m1, m2, m3, and m4 measured as described above, the density (Mg/m) was calculated based on the following formula 3 ) The calculated density divided by the density of water (1.00 Mg/m 3 ) The specific gravity of the rubber sample was determined.
(Density of rubber sample without counterweight)
Density=m1/(m 1-m 2)
(Density of rubber sample when weight was used)
Density=m1/(m1+m3-m 4)
[ Water content ]
Moisture content (%) according to JIS K6238-1: the measurement was performed by the oven a (volatile component measurement) method.
[pH]
After dissolving 6g (+ -0.05 g) of the acrylic rubber bag with 100g of tetrahydrofuran, 2.0ml of distilled water was added thereto, and after confirming complete dissolution, the pH was measured with a pH electrode.
[ Complex viscosity ]
The complex viscosity η was obtained by measuring the temperature dispersion (40 to 120 ℃) at a deformation 473% and 1Hz using a dynamic viscoelasticity measuring device "Rubber Process Analyzer RPA-2000" (manufactured by alpha technologies Co., ltd.), and obtaining the complex viscosity η at each temperature. Here, the dynamic viscoelasticity at 60 ℃ and the dynamic viscoelasticity at 100 ℃ are taken as the complex viscosity η (60 ℃) and the complex viscosity η (100 ℃) respectively, and the ratio η (100 ℃) and η (60 ℃) is calculated.
[ Mooney viscosity (ML1+4, 100 ℃)
Mooney viscosity (ML1+4, 100 ℃ C.) was measured according to the uncrosslinked rubber physical test method of JIS K6300.
[ Cross-Linkability ]
The crosslinkability of the rubber sample was determined by calculating the ratio of the change in the breaking strength of the rubber crosslinked material subjected to the secondary crosslinking for 2 hours to the change in the breaking strength of the rubber crosslinked material subjected to the secondary crosslinking for 4 hours ((breaking strength of the 4-hour crosslinked rubber crosslinked material/breaking strength of the 2-hour crosslinked rubber crosslinked material) ×100) according to the following criteria.
And (3) the following materials: the change rate of the breaking strength is less than 10 percent
X: the change rate of the breaking strength is more than 10 percent
[ roll processability ]
The roll processability of the rubber sample was evaluated by observing the roll-winding property and the state of the rubber when the rubber sample was rolled, according to the following criteria.
And (3) the following materials: the rubber composition was easily kneaded and wound around a roll, and separation from the roll was not observed, and the surface of the rubber composition after kneading was smooth
O: the kneading was easy, winding around the rolls was easy, separation from the rolls was not observed, and a small amount of irregularities were observed on the surface of a part of the rubber composition after kneading
And ∈: easy kneading, excellent roll windability, and the surface of the rubber composition after kneading has some irregularities
Delta: the kneading is easy, the roll-winding property is slightly poor, and the surface of the rubber composition after the kneading is rough
X: the roll windability was also poor when a load was applied to kneading
[ Banbury processability ]
The banbury processability of the rubber sample was evaluated by charging the rubber sample into a banbury mixer heated to 50 ℃ for 1 minute, charging the compounding agent a compounded in the rubber mixture described in table 1, integrating the rubber mixture in the first stage, and measuring BIT (carbon black mixing time, black Incorporation Time), which is the time until the maximum torque value was shown, to evaluate the index of comparative example 1 as 100 (the processability was more excellent as the index was smaller).
[ evaluation of storage stability ]
The storage stability of the rubber sample was evaluated by placing the rubber sample in a constant temperature and humidity tank (SH-222 manufactured by espek) at 45 ℃ x 80% rh, and calculating the rate of change in water content before and after 7 days of the test, and evaluating the index of comparative example 1 as 100 (the smaller the index, the more excellent the storage stability).
[ evaluation of Water resistance ]
The water resistance of the rubber sample was evaluated by immersing the crosslinked product of the rubber sample in distilled water at 85℃for 100 hours in accordance with JIS K6258, and the volume change rate before and after immersing was calculated in accordance with the following formula, and the water resistance was evaluated by using comparative example 1 as an index of 100 (the smaller the index, the more excellent the water resistance).
Rate of change in volume (%) = ((volume of test piece after immersion-volume of test piece before immersion) before and after immersion
Volume of test piece before immersion). Times. lO0
[ compression set resistance ]
The compression set resistance of the rubber sample was evaluated by measuring the compression set after leaving the rubber crosslinked product of the rubber sample to stand at 175℃for 90 hours in a state of being compressed by 25% in accordance with JIS K6262, and by evaluating the compression set according to the following criteria.
And (3) the following materials: compression set of less than 15%
X: compression set of 15% or more
[ evaluation of physical Properties in Normal state ]
The normal physical properties of the rubber sample were measured according to JIS K6251, and the breaking strength, 100% tensile stress and elongation at break of the rubber crosslinked product of the rubber sample were evaluated according to the following criteria.
(1) Breaking strength was evaluated as excellent at 10MPa or more and as X at less than 10 MPa. (2) 100% tensile stress, 5MPa or more was evaluated as excellent, and less than 5MPa was evaluated as X.
(3) Elongation at break was evaluated as excellent at 150% or more and as X at less than 150%.
[ evaluation of deviation of the amount of insoluble methyl ethyl ketone ]
The deviation evaluation of the methyl ethyl ketone insoluble component amount of the rubber sample was performed, and the methyl ethyl ketone insoluble component amount at 20 points arbitrarily selected from 20 parts (20 kg) of the rubber sample was measured and evaluated based on the following criteria.
And (3) the following materials: calculating the average value of the amount of methyl ethyl ketone insoluble components at 20 points, wherein all 20 points are within the range of + -3 of the average value
And (2) the following steps: calculating the average value of the methyl ethyl ketone insoluble component amounts at 20 points of measurement, wherein the total of 20 points of measurement is within the range of.+ -. 5 of the average value (1 out of 20 points of measurement is within the range of.+ -. 3 of the average value, but the total of 20 points is within the range of.+ -. 5 of the average value)
X: calculating the average value of the amount of methyl ethyl ketone insoluble components at 20 points, wherein 1 of the 20 points is out of the range of + -5
[ evaluation of processing stability Using Mooney scorch inhibition ]
The mooney scorch stability of the acrylic rubber composition was evaluated for the cooling rate of the sheet-like acrylic rubber extruded from the screw type biaxial extrusion dryer described in japanese patent No. 6683189.
Example 1
As shown in Table 2-1, in a mixing vessel having a homomixer, 46 parts of pure water, 4.5 parts of ethyl acrylate, 64.5 parts of n-butyl acrylate, 29.5 parts of methoxyethyl acrylate and 1.5 parts of mono-n-butyl fumarate as monomer components were added, and 1.8 parts of sodium octoxyethylenephosphate as an emulsifier was stirred to obtain a monomer emulsion.
Into a polymerization reaction vessel equipped with a thermometer and a stirring device, 170 parts of pure water and 3 parts of the monomer emulsion obtained above were charged, and after cooling to 12℃under a nitrogen stream, 0.00033 parts of ferrous sulfate, 0.02 parts of sodium ascorbate, and 0.2 parts of potassium persulfate as an inorganic radical generator were added to initiate polymerization. The polymerization was continued by maintaining the temperature in the polymerization vessel at 23℃and continuously dropping the remaining portion of the monomer emulsion over 3 hours, adding 0.0072 part of n-dodecyl mercaptan after 50 minutes from the start of the reaction, adding 0.0036 part of n-dodecyl mercaptan after 100 minutes, and adding 0.4 part of sodium L-ascorbate after 120 minutes, and stopping the polymerization by adding hydroquinone as a polymerization terminator when the polymerization conversion reached approximately 100%, to obtain an emulsion polymerization solution.
Next, in 350 parts of a 2% aqueous magnesium sulfate solution (a coagulating liquid using magnesium sulfate as a coagulating agent) heated to 80 ℃ and vigorously stirred with a stirring blade of a stirring device at 600 revolutions (circumferential speed 3.1 m/s) in a coagulating tank having a thermometer and a stirring device, the emulsion polymerization liquid obtained above was heated to 80 ℃ and continuously added to coagulate the polymer, to obtain a coagulated slurry containing the acrylic rubber pellets and water as a coagulated material. While filtering the pellets from the slurry obtained, water was discharged from the solidified layer to obtain aqueous pellets.
194 parts of hot water (70 ℃) was added to the coagulation tank in which the filtered aqueous pellets remained and stirred for 15 minutes, the aqueous pellets were washed, then the water was discharged, 194 parts of hot water (70 ℃) was added again and stirred for 15 minutes, and washing of the aqueous pellets was performed (the total number of washing times was 2). The washed aqueous pellet (aqueous pellet temperature 65 ℃) was fed to a screw type biaxial extrusion dryer 15, dehydrated and dried, and a sheet-like dried rubber having a width of 300mm and a thickness of 10mm was extruded. Then, the sheet-like dry rubber was cooled at a cooling rate of 200℃per hour using a conveyor type cooling device provided in direct connection with the screw type biaxial extrusion dryer 15.
The screw type biaxial extrusion dryer used in example 1 was composed of 1 feeder cylinder, 3 dehydrators (1 st to 3 rd dehydrators), and 5 dryer cylinders (1 st to 5 th dryer cylinders). The 1 st dewatering cylinder discharges water, and the 2 nd and 3 rd dewatering cylinders discharge steam. The operating conditions of the screw type biaxial extrusion dryer are as follows.
Water content:
water content of the aqueous pellets after drainage in the 1 st dewatering barrel: 20 percent of
Moisture content of the aqueous pellets after steam venting in the 3 rd dewatering barrel: 10 percent of
Moisture content of dried aqueous pellets in dryer barrel 5: 0.4%
Rubber temperature:
temperature of the aqueous pellets fed to the feed barrel: 65 DEG C
Temperature of rubber discharged from screw type biaxial extrusion dryer: 140 DEG C
Set temperature of each barrel:
1 st dewatering barrel: 100 DEG C
2 nd dewatering barrel: 120 DEG C
3 rd dewatering barrel: 120 DEG C
1 st dryer barrel: 120 DEG C
Dryer barrel 2: 130 DEG C
3 rd dryer barrel: 140 DEG C
4 th dryer barrel: 160 DEG C
5 th dryer barrel: 180 DEG C
Operating conditions:
diameter of screw (D): 132mm
Screw complete plant (L): 4620mm
·L/D：35
Rotational speed of the screw: 135rpm
Vacuum of the dryer barrel: 10kPa
Extrusion amount of rubber from die: 700 kg/hr
Resin pressure in die: 2MPa of
Maximum torque in screw type biaxial extrusion dryer: 15 N.m
The extruded sheet-like dry rubber was cooled to 50℃and then cut by a cutter, and 20 parts (20 kg) of the sheet-like dry rubber was laminated while the sheet-like dry rubber was still below 40℃to obtain an acrylic rubber bag (A). The reactive group content, ash component content, methyl ethyl ketone insoluble component content, pH, specific gravity, glass transition temperature (Tg), water content, molecular weight distribution, and complex viscosity at 100℃and 60℃of the obtained acrylic rubber bag (A) were measured and are shown in tables 2-2. Further, the storage stability test of the acrylic rubber bag (A) was conducted to determine the water content change rate, and the results are shown in Table 2-2.
Next, 100 parts of the acrylic rubber bag (A) and the compounding agent A of "formulation 1" shown in Table 1 were charged into a Banbury mixer, and mixed at 50℃for 5 minutes (first-stage mixing). BIT at this time was measured, and the Banbury processability of the acrylic rubber bag was evaluated, and the results are shown in Table 2-2.
Next, the resulting mixture was moved to a roller at 50℃and compounded with the compounding agent B of "formula 1" and mixed (second stage mixing) to obtain a rubber composition. The roll processability at this time was evaluated, and the results are shown in Table 2-2.
TABLE 1
Figure BDA0004113404120000671
1: SEAST3 (HAF) in the table is carbon black (manufactured by Tokida carbon Co., ltd.).
2: NOCRAC CD in the tables is 4,4' -bis (. Alpha.,. Alpha. -dimethylbenzyl) diphenylamine (manufactured by Dain Ind.).
3: rhenogranXLA-60 in the table is a vulcanization accelerator (manufactured by Langsheng Co.).
The obtained rubber composition was placed in a metal mold having a length of 15cm, a width of 15cm and a depth of 0.2cm, and was pressed at 180℃for 10 minutes while being pressurized by a pressing pressure of 10MPa, whereby primary crosslinking was performed, and the obtained primary crosslinked product was further heated by a Gill oven at 180℃for 2 hours to perform secondary crosslinking, whereby a sheet-like crosslinked rubber product was obtained. Then, a test piece of 3 cm. Times.2 cm. Times.0.2 cm was cut out from the resulting sheet-like crosslinked rubber, and the water resistance, compression set resistance and normal physical properties were evaluated. Further, the physical properties of the sheet-like rubber crosslinked product subjected to secondary crosslinking for 2 hours were measured in order to evaluate the crosslinkability. The results are shown in Table 2-2.
Example 2
An acrylic rubber bag (B) was obtained in the same manner as in example 1, except that the emulsifier was changed to 1.8 parts of nonylphenoxy hexaoxyethylene phosphate sodium salt, the amount of the inorganic radical generator potassium persulfate was changed to 0.21 part, and further, the post-addition of the chain transfer agent n-dodecyl mercaptan was changed to 0.017 part after 50 minutes, 0.017 part after 100 minutes and 0.017 part after 120 minutes, and the properties were evaluated. The results are shown in Table 2-2.
Example 3
An acrylic rubber bag (C) was obtained in the same manner as in example 1 except that the monomer components were changed to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.75 parts of mono-n-butyl fumarate, the emulsifier was changed to 1.8 parts of sodium tridecyloxy hexaoxyethylene phosphate, and the washed aqueous pellets were dried to a water content of 0.4% by using a hot air dryer at 160℃to obtain pellet-like acrylic rubber, which was then packed in a 300X 650X 300mm packer and compacted at a pressure of 3MPa for 25 seconds to obtain a rubber bag-like acrylic rubber. The properties of the acrylic rubber bag (C) were evaluated (the compounding agent was changed to "formula 2"), and the results are shown in Table 2-2.
Example 4
An acrylic rubber bag (D) was obtained in the same manner as in example 3 except that the monomer components were changed to 28 parts of ethyl acrylate, 38 parts of n-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allyl glycidyl ether, and each characteristic was evaluated (the compounding agent was changed to "formula 3"). The results are shown in Table 2-2.
Example 5
An acrylic rubber bag (E) was obtained in the same manner as in example 3 except that the monomer components were changed to 42.2 parts of ethyl acrylate, 35 parts of n-butyl acrylate, 20 parts of methoxyethyl acrylate, 1.5 parts of acrylonitrile and 1.3 parts of vinyl chloride acetate, and each characteristic was evaluated (the compounding agent was changed to "formula 4"). The results are shown in Table 2-2.
Example 6
An acrylic rubber bag (F) was obtained in the same manner as in example 2 except that the monomer components were changed to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.75 parts of mono-n-butyl fumarate, the emulsifier was changed to 1.8 parts of sodium tridecyloxy hexaoxyethylene phosphate, and the washed aqueous pellets were dried to a water content of 0.4% by using a hot air dryer at 160℃to obtain pellet-like acrylic rubber, which was then packed in a 300X 650X 300mm packer and compacted at a pressure of 3MPa for 25 seconds to obtain a rubber bag-like acrylic rubber. The properties of the acrylic rubber bag (F) were evaluated (the compounding agent was changed to "formula 2"), and the results are shown in Table 2-2.
Example 7
An acrylic rubber bag (G) was obtained in the same manner as in example 6 except that the monomer components were changed to 28 parts of ethyl acrylate, 38 parts of n-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allyl glycidyl ether, and each characteristic was evaluated (the compounding agent was changed to "formula 3"). The results are shown in Table 2-2.
Example 8
An acrylic rubber bag (H) was obtained in the same manner as in example 7 except that the monomer components were changed to 42.2 parts of ethyl acrylate, 35 parts of n-butyl acrylate, 20 parts of methoxyethyl acrylate, 1.5 parts of acrylonitrile and 1.3 parts of vinyl chloride acetate, and each characteristic was evaluated (the compounding agent was changed to "formula 4"). The results are shown in Table 2-2.
Example 9
An acrylic rubber bag (I) was obtained and evaluated for each characteristic in the same manner as in example 8, except that the amount of the inorganic radical generator potassium persulfate was changed to 0.22 part, and 0.025 part of the chain transfer agent n-dodecyl mercaptan was continuously added to the monomer emulsion without post-addition. The results are shown in Table 2-2.
Comparative example 1
A pellet-like acrylic rubber (J) was obtained in the same manner as in example 9, except that a 0.7% aqueous magnesium sulfate solution was added to the stirred emulsion polymerization solution (stirring number 100rpm, circumferential speed 0.5 m/s) after emulsion polymerization to carry out a coagulation reaction, and that the acrylic rubber was not subjected to encapsulation by a packer to obtain a pellet-like acrylic rubber, and each property was evaluated. The results are shown in Table 2-2.
Comparative example 2
The procedure of example 9 was repeated except that the emulsifier was changed to 0.709 part of sodium lauryl sulfate and 1.82 parts of polyoxyethylene lauryl ether, sodium sulfate was added to the stirred emulsion polymerization solution (stirring number 100rpm, circumferential speed 0.5 m/s) after emulsion polymerization to carry out coagulation reaction, 194 parts of industrial water was added in the washing step to wash the aqueous pellets, and after stirring at 25℃for 5 minutes in the coagulation tank, water was discharged from the coagulation tank, and the above procedure was carried out only 2 times and without encapsulation by a packer to obtain a pellet-like acrylic rubber, and the pellet-like acrylic rubber (K) was obtained to evaluate each property. The results are shown in Table 2-2.
[ Table 2-1]
Figure BDA0004113404120000701
[ Table 2-2]
Figure BDA0004113404120000711
As is clear from tables 2-1 and 2-2, the acrylic rubber bags (A) to (I) of the present invention contain an acrylic rubber having a reactive group selected from at least one of a carboxyl group, an epoxy group and a chlorine atom, and having a methyl ethyl ketone insoluble content of 50 wt% or less and an ash content of 0.4 wt% or less, and the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the absolute molecular weight distribution measured by GPC-MALS method using a dimethylformamide-based solvent as an eluting solvent is 3.4 or more, and the roll processability, banbury processability, water resistance and compression set resistance of the acrylic rubber bags (A) to (I) are highly balanced, and further, the storage stability, crosslinkability and normal physical properties including strength characteristics are also remarkably excellent (examples 1 to 9).
Further, as is clear from tables 2 to 2, the acrylic rubber packages (a) to (I) and the pellet-like acrylic rubbers (J) to (K) produced under the conditions of examples and comparative examples of the present invention have a reactive group of any one of a carboxyl group, an epoxy group and a chlorine atom and have a large weight average molecular weight (Mw), and therefore are excellent in crosslinkability, compression set resistance and normal physical properties including strength characteristics (examples 1 to 9 and comparative examples 1 to 2). However, the pellet-like acrylic rubbers (J) to (K) were inferior in roll processability, banbury processability, water resistance and storage stability (comparative example 1), and in water resistance and storage stability (comparative example 2).
As is clear from tables 2 to 2, in the case where the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is large, it is preferably 3.4 or more, more preferably 3.7 or more, still more preferably 4 or more, and in this case, the roll processability can be improved without impairing the strength characteristics (comparison of examples 1 to 9 and comparative example 2 with comparative example 1)
As is clear from tables 2-1 and 2-2, the acrylic rubber compositions having excellent strength characteristics and excellent roll processability and having a broad Mw/Mn ratio can be produced by using specific amounts of the inorganic radical generator and the chain transfer agent, in particular n-dodecyl mercaptan (examples 1 to 9). Further, as is clear from tables 2 to 2, by reducing the amount of the inorganic radical generator to be used and adding n-dodecyl mercaptan after it is added in batches without being added initially, it is possible to further improve the roll processability without impairing the strength characteristics (examples 1 to 8) as compared with continuously adding n-dodecyl mercaptan (example 9). This is to lengthen one polymer chain length by reducing the inorganic radical generator and not adding a chain transfer agent at the beginning, but although two distinct peaks are not formed in the GPC diagram, the high molecular weight component and the low molecular weight component are produced in good balance, the Mw is increased and the Mw/Mn is widened, and the strength characteristics and the roll processability are highly balanced. In order to effectively widen the Mw/Mn, the number of times of batch post-addition is greatly influenced as compared with the difference in the addition amount of the chain transfer agent in batches, and the Mw/Mn is widened 2 times as compared with the number of times of batch post-addition of 3 times (comparison of examples 3 to 5 and examples 6 to 8), and the continuous addition of the chain transfer agent limits the Mw/Mn to a certain extent (example 9). In addition, although not shown in table 2-2, in the present example, sodium ascorbate as a reducing agent was added 120 minutes after initiation of polymerization, and by doing so, the formation of high molecular weight components of the acrylic rubber became easy, and the effect of widening Mw/Mn of the addition after the chain transfer agent was increased. On the other hand, although not shown in Table 2-1, when polymerization is carried out using an organic radical generator, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) does not become wide, and the roll processability is poor, which is not preferable. Although not shown in Table 2-1, when the Mw/Mn is too large, for example, 10 or more, the low-molecular-weight component tends to be large and the strength characteristics tend to be poor by excessively increasing the amount of the chain transfer agent.
As is clear from tables 2 to 2, regarding the banbury workability, the banbury workability of the acrylic rubber bag having a small amount of methyl ethyl ketone insoluble component was excellent in relation to the amount of methyl ethyl ketone insoluble component of the acrylic rubber bag (comparison of examples 1 to 9 and comparative example 1). It was found that by performing emulsion polymerization in the presence of a chain transfer agent, the amount of methyl ethyl ketone insoluble components in the acrylic rubber bag (examples 3 to 8 and comparative example 2) can be reduced, and particularly when the polymerization conversion rate is increased in order to improve the strength characteristics, the amount of methyl ethyl ketone insoluble components increases sharply, and therefore, in examples 3 to 8, in which a chain transfer agent is added later in the latter half of emulsion polymerization, the formation of methyl ethyl ketone insoluble components can be suppressed. Further, by drying the aqueous pellets with a screw type biaxial extrusion dryer, the amount of methyl ethyl ketone insoluble components of the acrylic rubber bag was significantly reduced, and the banbury processability of the produced acrylic rubber bag was significantly improved (comparison of examples 1 to 2 and examples 3 to 8). In the present invention, although not shown in the present example, it was confirmed that the melt kneading was carried out in a screw-type biaxial extrusion dryer in a state of substantially no moisture (moisture content less than 1% by weight), the methyl ethyl ketone insoluble component amount was drastically increased in the emulsion polymerization without adding a chain transfer agent (comparative example 1) and the methyl ethyl ketone insoluble component deviation amount was almost disappeared, and the banbury processability was greatly improved without impairing the strength characteristics of the acrylic rubber bag.
As is clear from tables 2 to 2, the acrylic rubber bags (A) to (I) of the present invention are excellent in water resistance (comparison of examples 1 to 9 with comparative examples 1 to 2). As is clear from the observation of the influence of the difference in reactive groups on the water resistance in examples 3 to 9 having the same ash amount, the acrylic rubber bags (C, F) of examples 3 and 6 having carboxyl groups and the acrylic rubber bags (D, G) of reference examples 4 and 7 having epoxy groups are 2 times more excellent than the acrylic rubber bags (E, H, I) of examples 5, 8 and 9 having chlorine atoms. It is apparent from tables 2 to 2 that the total element amount of phosphorus, magnesium, sodium, calcium and sulfur in the ash of the acrylic rubber bags (a) to (I) of the present invention and the acrylic rubber bags (J) to (K) of the comparative examples is more than 90% by weight, and that the acrylic rubber bags are excellent in water resistance, mold releasability and other properties, and particularly, the water resistance is improved as the ratio of phosphorus to magnesium in the ash is increased (comparison between examples 1 to 9 and comparative example 1).
Further, as is clear from tables 2 to 2, the acrylic rubber bags (a) to (I) excellent in roll processability and banbury processability and also greatly excellent in water resistance were produced by adding a chain transfer agent to an emulsion polymerization liquid continuously or batchwise using an inorganic radical generator, and by adding the coagulation liquid to the stirred coagulation liquid instead of the emulsion polymerization liquid, and by performing a coagulation reaction, more preferably by vigorously stirring the coagulation liquid (stirring number 600 rpm/circumferential speed 3.1 m/s) and increasing the coagulant concentration of the stirred coagulation liquid (comparison of examples 1 to 9 with comparative example 1). As will be described later, this coagulation reaction produces small aqueous aggregates having a particle size in the range of 710 μm to 4.75mm, and the removal efficiency of the emulsifier and coagulant in the washing and dewatering steps is greatly improved, and the water resistance can be greatly improved by reducing the ash content in the acrylic rubber bag.
It is also clear from tables 2 to 2 that the reactive groups are more excellent than chlorine atoms in the case of carboxyl groups and epoxy groups (comparison of examples 3 to 4 and examples 6 to 7 with examples 5 and 8).
Further, as is clear from tables 2 to 2, the ash content of the acrylic rubber packs (a) to (B) dehydrated (water squeezed) before drying the hydrous pellets was significantly reduced, and the water resistance was improved (comparison of examples 1 to 2 and examples 3 to 9). In addition, when the amounts of components in ash of the acrylic rubber packages (a) to (B) were observed, most of them were phosphorus (P) and magnesium (Mg), and it is assumed that this is because the sodium phosphate salt in the emulsifier undergoes salt exchange with magnesium sulfate in the coagulant, and is contained in the aqueous pellet as magnesium phosphate, which cannot be sufficiently removed in the washing step, but can be reduced by dehydration (extrusion). Further, it was found that the ash content of the acrylic rubber bag was not deteriorated in water resistance when the ash content was mainly phosphorus and magnesium (comparative examples 1 to 9 and comparative examples 1 and 2).
As is clear from tables 2 to 2, the acrylic rubber bags (a) to (I) of the present invention were excellent in roll processability, banbury processability, water resistance and compression set resistance, and also were remarkably excellent in storage stability (examples 1 to 9). It is found that the storage stability of the acrylic rubber is greatly related to the specific gravity of the acrylic rubber, and when the specific gravity is large, the acrylic rubber does not trap air, and the storage stability is excellent (comparative examples 1 to 2, examples 3 to 9, and comparative examples 1 to 2). The acrylic rubber bag having a high specific gravity can be obtained by compacting a pellet-shaped acrylic rubber by a packer to form a bag (examples 3 to 9), and more preferably by extruding the acrylic rubber bag into a sheet or laminated by a screw type biaxial extrusion dryer to form a bag (examples 1 to 2). In the present invention, it was found that, in particular, an acrylic rubber bag obtained by laminating sheet-like acrylic rubber obtained by melt kneading and drying under reduced pressure, the storage stability was significantly improved without impairing the short-time crosslinkability, roll processability, compression set resistance, normal physical properties including strength properties, and water resistance (examples 1 to 2). Further, it is found that the storage stability of the acrylic rubber bag is more preferable when the ash content is smaller or the pH is within a specific range (examples 1 to 9).
[ particle size of resulting hydrous pellets ]
The proportion of (1) 710 μm to 6.7mm (6.7 mm without passing through 710 μm), (2) 710 μm to 4.75mm (4.75 mm without passing through 710 μm), and (3) 710 μm to 3.35mm (3.35 mm without passing through 710 μm) with respect to the total amount of the aqueous pellets produced in the coagulation step of examples 1 to 9 and comparative example 1 was measured using a JIS sieve. The results are shown below.
Example 1: (1) 90 wt%, (2) 90 wt%, (3) 87 wt%
Example 2: (1) 92 wt%, (2) 91 wt%, and (3) 89 wt%
Example 3: (1) 89 wt%, (2) 87 wt%, and (3) 83 wt%
Example 4: (1) 91 wt%, (2) 90 wt%, and (3) 83 wt%
Example 5: (1) 93 wt%, (2) 91 wt%, and (3) 89 wt%
Example 6: (1) 95 wt%, (2) 89 wt%, and (3) 80 wt%
Example 7: (1) 92 wt%, (2) 92 wt%, (3) 88 wt%
Example 8: (1) 94 wt%, (2) 93 wt%, (3) 87 wt%
Example 9: (1) 90 wt%, (2) 89 wt%, and (3) 88 wt%
Comparative example 1: (1) 15 wt%, (2) 1 wt%, (3) 0 wt%
From the results, it was found that even when the same washing was performed with the size of the aqueous aggregates produced in the coagulation step, the amount of ash remaining in the acrylic rubber bag was different, and that the aqueous aggregates having a large specific ratio of (1) to (3) were high in washing efficiency, low in ash amount, and excellent in water resistance (comparison between examples 3 to 9 of tables 2-2 and comparative example 1). Further, it was found that the ash removal rate at the time of dehydration of 20 wt% was also high even when the specific ratio of the aqueous pellets of (1) to (3) was large, the ash amount was further reduced, and the water resistance of the acrylic rubber bag was significantly improved (comparison of examples 1 to 2 and examples 3 to 9).
For reference, the procedure was carried out in the same manner as in comparative example 1 (reference example 2) except that the emulsion polymerization liquid was added to the coagulation liquid in the coagulation step (reference example 1), and the coagulant concentration of the coagulation liquid was changed from 0.7% by weight to 2% by weight, except that the particle size ratio of the produced aqueous pellets and the ash content in the acrylic rubber were measured in the same manner as in comparative example 1.
Reference example 1: (1) 90 wt%, (2) 55 wt%, and (3) 22 wt%, and ash content 0.55 wt%
Reference example 2: 91 wt%, 70 wt%, 40 wt% and 0.41 wt% ash
From the results, it was found that the ash content in the acrylic rubber was increased (2%) during the coagulation reaction, and the method was changed to a method (Lx ∈) in which the emulsion polymerization liquid was added to the stirred coagulation liquid, and the stirring of the coagulation liquid was vigorously performed (stirring number 600 rpm/peripheral speed 3.1 m/s), so that the particle size of the produced aqueous pellets could be concentrated in a specific range of 710 μm to 4.75mm, the washing efficiency with hot water and the removal efficiency of the emulsifier and coagulant during dehydration were significantly improved, the ash content of the acrylic rubber bag could be reduced, and the water resistance could be significantly improved without impairing the properties such as crosslinking property, roll workability, compression set resistance, and normal physical properties including strength properties of the acrylic rubber (examples 1 to 2). In addition, it was confirmed that the presence or absence of the addition of the chain transfer agent had no effect on the particle size of the resulting aqueous pellet.
Example 10
Acrylic rubber (L) was obtained in the same manner as in example 2 except that the monomer components were changed to 74.5 parts of ethyl acrylate, 17 parts of n-butyl acrylate, 7 parts of methoxyethyl acrylate and 1.5 parts of mono-n-butyl fumarate, and the emulsifier was changed to 1.8 parts of sodium tridecyloxy hexaoxyethylene phosphate, as shown in Table 3-1, and the properties were evaluated, and the results are shown in Table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 11
Acrylic rubber (M) was obtained in the same manner as in example 1 except that the monomer components were changed to 74.5 parts of ethyl acrylate, 17 parts of n-butyl acrylate, 7 parts of methoxyethyl acrylate, 1.5 parts of mono-n-butyl fumarate, and 1.8 parts of tridecyloxy hexaoxyethylene phosphate sodium salt, and the properties were evaluated, and the results are shown in tables 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 12
Acrylic rubber (N) was obtained in the same manner as in example 10 except that the monomer components were changed to 28 parts of ethyl acrylate, 38 parts of N-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allyl glycidyl ether, and the operating conditions of the screw-type biaxial extrusion dryer were changed to high shear (maximum torque 45n·m), and the properties (compounding agent was changed to "formula 3"), and the results were evaluated as shown in table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 13
An acrylic rubber (O) was obtained in the same manner as in example 12 except that the monomer components were changed to 48.5 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.5 parts of mono-n-butyl fumarate, and the properties (the compounding agent was changed to "formula 1") were evaluated, and the results are shown in Table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 14
An acrylic rubber (P) was obtained in the same manner as in example 12 except that the monomer components were changed to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.75 parts of mono-n-butyl fumarate, and each characteristic was evaluated (compounding agent was changed to "formula 2"), and the results are shown in table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 15
An acrylic rubber (Q) was obtained in the same manner as in example 11 except that the monomer components were changed to 28 parts of ethyl acrylate, 38 parts of N-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allyl glycidyl ether, and the operating conditions of the screw-type biaxial extrusion dryer were changed to high shear (maximum torque 45n·m), and the properties (compounding agent was changed to "formula 3"), and the results were evaluated as shown in tables 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 16
An acrylic rubber (R) was obtained in the same manner as in example 15 except that the monomer components were changed to 48.5 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.5 parts of mono-n-butyl fumarate, and each characteristic was evaluated (the compounding agent was changed to "formula 1"), and the results are shown in table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
Example 17
An acrylic rubber (S) was obtained in the same manner as in example 15 except that the monomer components were changed to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.75 parts of mono-n-butyl fumarate, and each characteristic was evaluated (compounding agent was changed to "formula 2"), and the results are shown in Table 3-2. In addition, table 3-1 shows the post-dewatering (draining) water content, maximum torque, specific power, specific energy consumption, shear rate, and shear viscosity of the screw type biaxial extrusion dryer.
[ Table 3-1]
Figure BDA0004113404120000781
[ Table 3-2]
Figure BDA0004113404120000791
As is clear from tables 3-1 and 3-2, the acrylic rubber (N) to (S) of the present invention is excellent in Banbury workability, water resistance, storage stability, crosslinking property, compression set resistance and normal physical properties including strength characteristics, and is significantly improved in roll workability (comparison of examples 12 to 17 with examples 10 to 11). This is an acrylic rubber comprising a high molecular weight component and a low molecular weight component, which is emulsion polymerized by post-addition of a chain transfer agent, is dried with high shear using a screw type biaxial extrusion dryer, and further an acrylic rubber having a balanced molecular weight and molecular weight distribution is obtained, whereby the roll processability can be significantly improved.
Further, the variation in the amount of methyl ethyl ketone insoluble component was evaluated for each rubber sample by the method described above. Specifically, the amount of methyl ethyl ketone insoluble component at 20 selected arbitrarily from 20 parts (20 kg) of the rubber sample was measured, and the deviation evaluation of the amount of methyl ethyl ketone insoluble component of the rubber sample was performed based on the above reference.
When the deviation evaluation of the methyl ethyl ketone insoluble component amount was performed using the acrylic rubber packs (L) to (S) obtained in examples 10 to 17 and the pellet-like acrylic rubber (J) obtained in comparative example 1 as rubber samples, the results of the acrylic rubber packs (L) to (S) of examples 10 to 17 of the present invention were all "-" and the result of the pellet-like acrylic rubber (J) of comparative example 1 was "×".
From these results, it is assumed that the acrylic rubber bags (L) to (S) are melt-kneaded by a screw type biaxial extruder, and melt-kneaded and dried in a state where substantially no moisture is present (the moisture content is less than 1% by weight), so that the amount of methyl ethyl ketone insoluble components is almost eliminated, and the variation in the amount of methyl ethyl ketone insoluble components is almost eliminated, whereby the banbury processability can be remarkably improved without impairing the crosslinkability, roll processability, compression set resistance, and normal physical properties including strength characteristics.
On the other hand, it was found that the aqueous pellets produced by emulsion polymerization and coagulation washing under the conditions for producing the pellet-like acrylic rubber (J) of comparative example 1 were fed into a screw type biaxial extrusion dryer under the same conditions as in example 10 and extrusion-dried, and the amount of methyl ethyl ketone insoluble component and the amount deviation of methyl ethyl ketone insoluble component measured on the obtained acrylic rubber were substantially the same as those of the acrylic rubber bag (L), and the banbury processability was improved, but the roll processability was evaluated as "x".
Regarding the acrylic rubber compositions comprising the acrylic rubber packages (L) to (S) of examples 10 to 17, the Mooney scorch storage stability was evaluated according to the following criteria by the method of the above-mentioned evaluation of processing stability by Mooney scorch inhibition, by measuring the Mooney scorch time t5 (minutes) at a temperature of 125℃according to JIS K6300. The results were excellent.
And (3) the following materials: the Mooney scorch time t5 is more than 2.0 minutes
And (2) the following steps: the Mooney scorch time t5 is 1.5 to 2.0 minutes
X: the Mooney scorch time t5 is less than 1.5 minutes
In the acrylic rubber packages (L) to (S), the cooling rate of the sheet-like dry rubber extruded from the screw type biaxial extrusion dryer was as high as approximately 200℃per hour, and was 40℃per hour or more, as in example 1.
[ Release to Metal mold ]
The rubber compositions of the acrylic rubber bags (L) to (S) obtained in examples 10 to 17 were pressed in
Figure BDA0004113404120000801
The crosslinked rubber product crosslinked at 165℃for 2 minutes was taken out of the mold, and when the mold releasability was evaluated according to the following criteria, the acrylic rubber bags (L) to (S) were all evaluated as excellent.
And (3) the following materials: can be easily released from the metal mold without mold residue
O: can be easily released from the metal mold but little mold residue is found
Delta: can be easily released from a metal mold but has a small amount of mold residues
X: difficult to release from a metal mold
Description of the reference numerals
1 acrylic rubber manufacturing System
3 coagulation device
4 cleaning device
5 screw extruder
6 Cooling device
7 glue packaging device

Claims (46)

1. An acrylic rubber bag, which consists of acrylic rubber,
and the amount of methyl ethyl ketone insoluble component in the acrylic rubber bag is 50 wt% or less and the amount of ash is 0.4 wt% or less,
the acrylic rubber has a reactive group selected from at least one of a carboxyl group, an epoxy group, and a chlorine atom,
the acrylic rubber has a ratio (Mw/Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) of 3.4 or more, as measured by GPC-MALS method using a dimethylformamide-based solvent as an eluting solvent.
2. The acrylic rubber bag according to claim 1, wherein the amount of methyl ethyl ketone insoluble component of the acrylic rubber bag is 10% by weight or less.
3. The acrylic rubber bag according to claim 1 or 2, wherein the acrylic rubber bag has values in a range of (average ± 5% by weight) all at 20 measured methyl ethyl ketone insoluble component amounts.
4. The acrylic rubber bag according to any one of claims 1 to 3, wherein the specific gravity of the acrylic rubber bag is 0.8 or more.
5. The acrylic rubber bag according to any one of claims 1 to 4, wherein the ash content of the acrylic rubber bag is in the range of 0.001 to 0.2% by weight.
6. The acrylic rubber bag according to any one of claims 1 to 5, wherein the total amount of sodium, magnesium, calcium, phosphorus and sulfur in ash of the acrylic rubber bag is 50% by weight or more.
7. The acrylic rubber bag according to any one of claims 1 to 6, wherein the total amount of magnesium and phosphorus in ash of the acrylic rubber bag is 50% by weight or more.
8. The acrylic rubber bag according to any one of claims 1 to 7, wherein the acrylic rubber bag has a weight average molecular weight (Mw) of 100 ten thousand or more as measured by GPC-MALS method.
9. The acrylic rubber bag according to any one of claims 1 to 8, wherein the acrylic rubber bag has a ratio (Mw/Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) of an absolute molecular weight distribution measured by a GPC-MALS method of 3.5 or more.
10. The acrylic rubber bag according to any one of claims 1 to 8, wherein the acrylic rubber bag has a ratio (Mw/Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) of an absolute molecular weight distribution measured by a GPC-MALS method of 3.8 or more.
11. The acrylic rubber bag according to any one of claims 1 to 10, wherein the acrylic rubber bag has a ratio (Mz/Mw) of a z-average molecular weight (Mz) to a weight-average molecular weight (Mw) of an absolute molecular weight distribution measured by a GPC-MALS method of 1.3 or more.
12. The acrylic rubber bag according to any one of claims 1 to 11, wherein the acrylic rubber is emulsion-polymerized using a phosphate salt or a sulfate salt as an emulsifier.
13. The acrylic rubber bag according to any one of claims 1 to 12, wherein the acrylic rubber is obtained by coagulating and drying the emulsion-polymerized polymer liquid using an alkali metal salt or a group 2 metal salt of the periodic table as a coagulating agent.
14. The acrylic rubber bag according to any one of claims 1 to 13, wherein the acrylic rubber is obtained by melt kneading and drying after solidification.
15. The acrylic rubber bag according to claim 14, wherein the melt-kneading and drying are performed in a substantially moisture-free state.
16. The acrylic rubber bag according to claim 14 or 15, wherein the melt-kneading and drying are performed under reduced pressure.
17. The acrylic rubber bag according to any one of claims 14 to 16, wherein the acrylic rubber is cooled at a cooling rate of 40 ℃/hr or more after the melt-kneading and drying.
18. The acrylic rubber bag according to any one of claims 1 to 17, which is obtained by washing, dehydrating and drying an aqueous pellet having a particle diameter in the range of 710 μm to 6.7mm in a proportion of 50% by weight or more.
19. The manufacturing method of the acrylic rubber bag comprises the following steps:
an emulsifying step of emulsifying an acrylic rubber monomer component containing a monomer having a reactive group selected from at least one of a carboxyl group, an epoxy group, and a chlorine atom with water and an emulsifier;
An emulsion polymerization step of initiating polymerization in the presence of a redox catalyst containing an inorganic radical generator and a reducing agent, and adding a chain transfer agent in a batch after the polymerization step to continue the polymerization, thereby obtaining an emulsion polymerization solution;
a coagulation step of adding the emulsion polymerization liquid obtained to the stirred coagulation liquid to coagulate the emulsion polymerization liquid, thereby producing an aqueous pellet;
a washing step of washing the produced hydrous pellets with hot water;
a dehydration step of dehydrating the washed aqueous pellets;
a drying step of drying the dehydrated aqueous pellets to less than 1 wt%;
and a rubber coating step of coating the dried rubber with rubber.
20. The method for producing an acrylic rubber bag according to claim 19, wherein the acrylic rubber bag according to any one of claims 1 to 18 is produced.
21. The method for producing an acrylic rubber bag according to claim 19 or 20, wherein in the emulsion polymerization step, emulsion polymerization is performed using a phosphate salt or a sulfate salt as an emulsifier.
22. The method for producing an acrylic rubber bag according to any one of claims 19 to 21, wherein the polymerization liquid produced in the emulsion polymerization step is coagulated by using an alkali metal salt or a group 2 metal salt of the periodic table as a coagulant, and dried.
23. The method for producing an acrylic rubber bag as claimed in claim 22, wherein the polymerization liquid produced in the emulsion polymerization step is added to an aqueous solution containing a coagulant containing an alkali metal salt or a group 2 metal salt of the periodic table and stirred to be coagulated.
24. The method for producing an acrylic rubber bag according to any one of claims 19 to 23, wherein the polymerization liquid produced in the emulsion polymerization step is brought into contact with a coagulant, coagulated, and then melt kneaded and dried.
25. The method for producing an acrylic rubber bag according to claim 24, wherein the melt-kneading and drying are performed in a substantially moisture-free state.
26. The method for producing an acrylic rubber bag according to claim 24 or 25, wherein the melt-kneading and drying are performed under reduced pressure.
27. The method for producing an acrylic rubber bag according to any one of claims 24 to 26, wherein the acrylic rubber after melt-kneading and drying is cooled at a cooling rate of 40 ℃/hr or more.
28. The method for producing an acrylic rubber bag according to any one of claims 19 to 27, wherein the aqueous pellet having a particle diameter in the range of 710 μm to 6.7mm in a proportion of 50% by weight or more is washed, dehydrated and dried.
29. A rubber composition comprising a rubber component comprising the acrylic rubber bag according to any one of claims 1 to 18, a filler and a crosslinking agent.
30. The rubber composition according to claim 29, wherein the filler is a reinforcing filler.
31. The rubber composition according to claim 29, wherein the filler is a carbon black.
32. The rubber composition according to claim 29, wherein the filler is a silica type.
33. The rubber composition according to any one of claims 29 to 32, wherein the crosslinking agent is an organic crosslinking agent.
34. The rubber composition according to any one of claims 29 to 33, wherein the crosslinking agent is a multi-component compound.
35. The rubber composition according to any one of claims 29 to 34, wherein the crosslinking agent is an ion-crosslinkable compound.
36. The rubber composition according to claim 35, wherein the crosslinking agent is an ion-crosslinkable organic compound.
37. The rubber composition of claim 35 or 36, wherein the crosslinking agent is a polyionic organic compound.
38. The rubber composition according to any one of claims 35 to 37, wherein an ion of the ion-crosslinkable compound, the ion-crosslinkable organic compound or the polyion-organic compound as the crosslinking agent is an ion-reactive group selected from at least one of an amino group, an epoxy group, a carboxyl group and a thiol group.
39. The rubber composition according to claim 37, wherein the crosslinking agent is a polyion compound selected from at least one of a polyamine compound, a polyepoxide compound, a polycarboxylic acid compound, and a polythiol compound.
40. The rubber composition according to any one of claims 29 to 39, wherein the content of the crosslinking agent is in the range of 0.001 to 20 parts by weight relative to 100 parts by weight of the rubber component.
41. The rubber composition of any of claims 29-40, wherein the rubber composition further comprises an anti-aging agent.
42. The rubber composition according to claim 41, wherein the antioxidant is an amine-based antioxidant.
43. A process for producing a rubber composition comprising mixing the rubber component comprising the acrylic rubber bag according to any one of claims 1 to 18, a filler and an optionally used antioxidant, and then mixing the resulting mixture with a crosslinking agent.
44. A rubber crosslinked product obtained by crosslinking the rubber composition according to any one of claims 29 to 42.
45. A rubber crosslinked according to claim 44 wherein the crosslinking of the rubber composition is performed after molding.
46. A rubber crosslinked according to claim 44 or 45 wherein the crosslinking of the rubber composition is a crosslinking that proceeds in both primary and secondary crosslinking.
CN202180056988.1A 2020-06-05 2021-06-04 Acrylic rubber bag excellent in roll processability and banbury processability Pending CN116134058A (en)

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